Azure cosmosdb IChangeFeedObserver ProcessChangesAsync后出现奇怪异常

我正在尝试创建从CosmosDB到本地CouchBase Lite数据库的复制。为此，我使用Microsoft.Azure.Documents.ChangeFeedProcessor

但由于某些原因，总是在IChangeFeedObserver进程ChangesSync结束后，控制台上出现以下异常：

“错误”：[“未满足某一特定的先决条件”]是什么意思？复制成功地结束了，但这让我很烦恼

使用system.diagnostics更新了

ChangeFeedEventHost Information: 53 : 09/25/2017 08:27:54: Host 'TESTIkiosk' starting to check for available leases.
ChangeFeedEventHost Information: 54 : 09/25/2017 08:27:54: Host 'TESTIkiosk' starting to check for available leases.
ChangeFeedEventHost Information: 55 : 09/25/2017 08:27:54: Host 'TESTIkiosk' 1 partitions, 1 hosts, 0 available leases, target = 1, min = 0, max = 0, mine = 1, will try to take 0 lease(s) for myself'.
ChangeFeedEventHost Information: 56 : 09/25/2017 08:27:54: Host 'TESTIkiosk' 1 partitions, 1 hosts, 0 available leases, target = 1, min = 0, max = 0, mine = 1, will try to take 0 lease(s) for myself'.
ChangeFeedEventHost Information: 57 : 09/25/2017 08:28:06: Host 'TESTIkiosk' starting renewal of Leases.
ChangeFeedEventHost Information: 58 : 09/25/2017 08:28:06: Host 'TESTIkiosk' renewing lease for PartitionId '0' with lease token '"0000fa04-0000-0000-0000-59c893d40000"'
ChangeFeedEventHost Information: 59 : 09/25/2017 08:28:06: Host 'TESTIkiosk' starting renewal of Leases.
ChangeFeedEventHost Information: 60 : 09/25/2017 08:28:06: Host 'TESTIkiosk' renewing lease for PartitionId '0' with lease token '"0000fb04-0000-0000-0000-59c893d40000"'
ChangeFeedEventHost Information: 61 : 09/25/2017 08:28:06: Host 'TESTIkiosk' attempted to renew lease for PartitionId '0' and lease token '"0000fa04-0000-0000-0000-59c893d40000"' with result: 'True'
ChangeFeedEventHost Information: 62 : 09/25/2017 08:28:06: Host 'TESTIkiosk' attempted to renew lease for PartitionId '0' and lease token '"0000fb04-0000-0000-0000-59c893d40000"' with result: 'True'
ChangeFeedEventHost Information: 63 : 09/25/2017 08:28:07: Host 'TESTIkiosk' starting to check for available leases.
ChangeFeedEventHost Information: 64 : 09/25/2017 08:28:07: Host 'TESTIkiosk' starting to check for available leases.
ChangeFeedEventHost Information: 65 : 09/25/2017 08:28:07: Host 'TESTIkiosk' 1 partitions, 1 hosts, 0 available leases, target = 1, min = 0, max = 0, mine = 1, will try to take 0 lease(s) for myself'.
ChangeFeedEventHost Information: 66 : 09/25/2017 08:28:07: Host 'TESTIkiosk' 1 partitions, 1 hosts, 0 available leases, target = 1, min = 0, max = 0, mine = 1, will try to take 0 lease(s) for myself'.
[08:28:15 INF] Change feed in Ingredients: total 1 doc(s)
[08:28:15 INF] Replicated 2614
ChangeFeedEventHost Information: 67 : 09/25/2017 08:28:15: Partition '0' update failed because the lease with token '"0000e804-0000-0000-0000-59c893b20000"' was updated by same/this host with token '"00000005-0000-0000-0000-59c893e50000"'. Will retry, 4 retry(s) left.
ChangeFeedEventHost Information: 68 : 09/25/2017 08:28:15: Checkpoint: partition 0, new continuation '"81"'


DocDBTrace Error: 0 : DocumentClientException with status code PreconditionFailed, message: Message: {"Errors":["One of the specified pre-condition is not met"]}, inner exception: null, and response headers: {
"x-ms-last-state-change-utc": "Sun, 24 Sep 2017 21:03:48.392 GMT",
"lsn": "954",
"x-ms-schemaversion": "1.3",
"x-ms-quorum-acked-lsn": "954",
"x-ms-current-write-quorum": "3",
"x-ms-current-replica-set-size": "4",
"x-ms-documentdb-partitionkeyrangeid": "0",
"x-ms-xp-role": "1",
"x-ms-request-charge": "1.24",
"x-ms-serviceversion": " version=1.17.52.1",
"x-ms-activity-id": "b9877abb-6203-4408-b1c3-92c9f52aad67",
}
DocDBTrace Error: 0 : Operation will NOT be retried. Current attempt 0, Exception: Microsoft.Azure.Documents.PreconditionFailedException: Message: {"Errors":["One of the specified pre-condition is not met"]}
ActivityId: b9877abb-6203-4408-b1c3-92c9f52aad67, Request URI: /apps/c9c8f510-0ca7-4702-aa6c-9c596d797367/services/75cca430-a307-47a0-89aa-82aabf32e065/partitions/53fb63ca-95ae-4d13-90be-d32f1a88843c/replicas/131504697049132845p/
   at Microsoft.Azure.Documents.TransportClient.ThrowIfFailed(String resourceAddress, StoreResponse storeResponse, Uri physicalAddress, Guid activityId)
   at Microsoft.Azure.Documents.RntbdTransportClient.<InvokeStoreAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.ReplicatedResourceClient.<WriteAsync>d__1b.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.ReplicatedResourceClient.<InvokeAsync>d__b.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.ReplicatedResourceClient.<>c__DisplayClass1.<<InvokeAsync>b__0>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.BackoffRetryUtility`1.<>c__DisplayClassf`1.<<ExecuteAsync>b__d>d__11.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.BackoffRetryUtility`1.<ExecuteRetry>d__1b.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.Azure.Documents.BackoffRetryUtility`1.<ExecuteRetry>d__1b.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.BackoffRetryUtility`1.<ExecuteAsync>d__18`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.ReplicatedResourceClient.<InvokeAsync>d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.StoreClient.<ProcessMessageAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.Client.DocumentClient.<UpdateAsync>d__305.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.Client.DocumentClient.<ReplaceDocumentPrivateAsync>d__13d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.Client.DocumentClient.<ReplaceDocumentPrivateAsync>d__135.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.BackoffRetryUtility`1.<>c__DisplayClass2.<<ExecuteAsync>b__0>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Documents.BackoffRetryUtility`1.<ExecuteRetry>d__1b.MoveNext() 

ChangeFeedEventHost信息：53:09/25/2017 08:27:54:主机“TESTIkiosk”开始检查可用租约。
ChangeFeedEventHost信息：54:09/25/2017 08:27:54：主机“TESTIkiosk”开始检查可用租约。
ChangeFeedEventHost信息：55:09/25/2017 08:27:54：主机“TESTIkiosk”1个分区，1个主机，0个可用租约，目标=1，最小=0，最大=0，我的=1，将尝试为自己接受0个租约”。
ChangeFeedEventHost信息：56:09/25/2017 08:27:54：主机“TESTIkiosk”1个分区，1个主机，0个可用租约，目标=1，最小=0，最大=0，我的=1，将尝试为自己接受0个租约”。
ChangeFeedEvent主机信息：57:09/25/2017 08:28:06：主机“TESTIkiosk”开始续租。
ChangeFeedEventHost信息：58:09/25/2017 08:28:06:主机“TESTIkiosk”使用租约令牌“0000fa04-0000-0000-59c893d40000”续订分区“0”的租约
ChangeFeedEvent主机信息：59:09/25/2017 08:28:06：主机“TESTIkiosk”开始续租。
ChangeFeedEventHost信息：60:09/25/2017 08:28:06:主机“TESTIkiosk”使用租约令牌“0000fb04-0000-0000-0000-59c893d40000”续订分区“0”的租约
ChangeFeedEventHost信息：61:09/25/2017 08:28:06:主机“TESTIkiosk”尝试续订分区ID“0”和租约令牌“0000fa04-0000-0000-59c893d40000”的租约，结果为：“True”
ChangeFeedEventHost信息：62:09/25/2017 08:28:06:主机“TESTIkiosk”尝试续订分区ID“0”和租赁令牌“0000fb04-0000-0000-59c893d40000”的租赁，结果为：“True”
ChangeFeedEventHost信息：63:09/25/2017 08:28:07：主机“TESTIkiosk”开始检查可用租约。
ChangeFeedEventHost信息：64:09/25/2017 08:28:07：主机“TESTIkiosk”开始检查可用租约。
ChangeFeedEventHost信息：65:09/25/2017 08:28:07:主机“TESTIkiosk”1个分区，1个主机，0个可用租约，目标=1，最小=0，最大=0，我的=1，将尝试为自己接受0个租约”。
ChangeFeedEventHost信息：66:09/25/2017 08:28:07:主机“TESTIkiosk”1个分区，1个主机，0个可用租约，目标=1，最小=0，最大=0，我的=1，将尝试为自己接受0个租约”。
[08:28:15 INF]更换饲料成分：共1份文件
[08:28:15 INF]2614
ChangeFeedEventHost信息：67:09/25/2017 08:28:15:分区“0”更新失败，因为带有令牌“0000e804-0000-0000-0000-59c893b20000”的租约已由同一/此主机使用令牌“0000000 5-0000-0000-0000-59c893e50000”进行更新。将重试，剩余4次重试。
ChangeFeedEventHost信息：68:09/25/2017 08:28:15：检查点：分区0，新的继续“81”
DocDBTrace错误：0:DocumentClientException，状态代码为PremissionFailed，消息：消息：{“Errors”：[“未满足指定的前提条件之一”]}，内部异常：null，响应头：{
“x-ms-last-state-change-utc”：“2017年9月24日星期日21:03:48.392 GMT”，
“lsn”：“954”，
“x-ms-schemaversion”：“1.3”，
“x-ms-QUORM-acked-lsn”：“954”，
“x-ms-current-write-quorum”：“3”，
“x-ms-current-replica-set-size”：“4”，
“x-ms-documentdb-partitionkeyrangeid”：“0”，
“x-ms-xp-role”：“1”，
“x-ms-request-charge”：“1.24”，
“x-ms-serviceversion”：“version=1.17.52.1”，
“x-ms-activity-id”：“b9877abb-6203-4408-b1c3-92c9f52aad67”，
}
DocDBTrace错误：0:将不会重试该操作。当前尝试0，异常：Microsoft.Azure.Documents.PremissionFailedException:消息：{“错误”：[“未满足指定的前提条件之一”]}
活动ID:b9877abb-6203-4408-b1c3-92c9f52aad67，请求URI:/apps/c9c8f510-0ca7-4702-aa6c-9c596d797367/services/75cca430-a307-47a0-89aa-82aabf32e065/partitions/53fb63ca-95ae-4d13-90be-D32F188843C/replications/13150477049132845P/
位于Microsoft.Azure.Documents.TransportClient.ThrowIfFailed（字符串resourceAddress、StoreResponse StoreResponse、Uri physicalAddress、Guid activityId）
在Microsoft.Azure.Documents.rntbdtTransportClient.d_u0.MoveNext（）上
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
在Microsoft.Azure.Documents.ReplicatedResourceClient.d_u1b.MoveNext（）上
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
在Microsoft.Azure.Documents.ReplicatedResourceClient.d_ub.MoveNext（）上
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
在Microsoft.Azure.Documents.ReplicatedResourceClient.c__DisplayClass1.d__3.MoveNext（）上
---来自引发异常的上一个位置的堆栈结束跟踪---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务）
在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中
在Microsoft.Azure.Documents.BackoffRetryUtility`1.c\u显示类`1.d\u 11.MoveNext（）
---来自引发异常的上一个位置的堆栈结束跟踪---
在System.Runtime.CompilerServices上
    using Microsoft.Azure.Documents.ChangeFeedProcessor;
    using System;
    using System.Collections.Generic;
    using System.Threading;
    using System.Threading.Tasks;

    namespace Solteq.Pos.Repositories.Feeds
    {
        internal class MyHostFeed : IChangeFeedObserver
        {
            private int s_totalDocs = 0;
            private Func<dynamic, bool> replicate;
            private string name;

            public Func<dynamic, bool> Replicate { get => replicate; set => replicate = value; }
            public string Name { get => name; set => name = value; }

            public Task OpenAsync(ChangeFeedObserverContext context)
            {
                Console.WriteLine("Worker opened for {0}, {1}", name, context.PartitionKeyRangeId);
                return Task.CompletedTask;  // Requires targeting .NET 4.6+.
            }
            public Task CloseAsync(ChangeFeedObserverContext context, ChangeFeedObserverCloseReason reason)
            {
                Console.WriteLine("Worker closed for  {0}, {1}", name, context.PartitionKeyRangeId);
                return Task.CompletedTask;
            }

            public Task ProcessChangesAsync(ChangeFeedObserverContext context, IReadOnlyList<Microsoft.Azure.Documents.Document> docs)
            {
                Console.WriteLine("Change feed in {0}: total {1} doc(s)", name, Interlocked.Add(ref s_totalDocs, docs.Count));
                foreach (var one in docs)
                {
                    Console.WriteLine("Replicated: " + one.Id);
                    Replicate(one);
                }
                return Task.CompletedTask;
            }
        }
    }

        public async void StartReplication(string replicateFrom, string hostName, Func<dynamic, bool> replicate)
        {

            // Customizable change feed option and host options 
            ChangeFeedOptions feedOptions = new ChangeFeedOptions();

            // ie customize StartFromBeginning so change feed reads from beginning
            // can customize MaxItemCount, PartitonKeyRangeId, RequestContinuation, SessionToken and StartFromBeginning
            // feedOptions.StartFromBeginning = true;

            ChangeFeedHostOptions feedHostOptions = new ChangeFeedHostOptions();

            // ie. customizing lease renewal interval to 15 seconds
            // can customize LeaseRenewInterval, LeaseAcquireInterval, LeaseExpirationInterval, FeedPollDelay 
            //feedHostOptions.LeaseRenewInterval = TimeSpan.FromSeconds(15);
            feedHostOptions.LeasePrefix = replicateFrom;
            feedHostOptions.FeedPollDelay = TimeSpan.FromSeconds(60);

            try
            {
                DocumentCollectionInfo documentCollectionLocation = new DocumentCollectionInfo
                {
                    Uri = new Uri(_databaseServiceUri),
                    MasterKey = _databaseAuthKey,
                    DatabaseName = _databaseId,
                    CollectionName = replicateFrom
                };
                DocumentCollectionInfo leaseCollectionLocation = new DocumentCollectionInfo
                {
                    Uri = new Uri(_databaseServiceUri),
                    MasterKey = _databaseAuthKey,
                    DatabaseName = _databaseId,
                    CollectionName = "leases"
                };
                DocumentFeedObserverFactory docObserverFactory = new DocumentFeedObserverFactory(replicate, replicateFrom);
                ChangeFeedEventHost host = new ChangeFeedEventHost(hostName, documentCollectionLocation, leaseCollectionLocation, feedOptions, feedHostOptions);

                await host.RegisterObserverFactoryAsync(docObserverFactory);
                hosts.Add(host);
            }
            catch (Exception e)
            {
                Console.WriteLine("Replication process halted for (" + replicateFrom + ") reason: " + e.ToString());
                //throw e;
            }
        }