KeyNotFoundException when handling BasicCancelOK message

[LamarLugli]

Result: RegistrationFailed Already closed: The AMQP operation was interrupted: AMQP close-reason, initiated by Library, code=541, text='Unexpected Exception', classId=0, methodId=0, cause=System.Collections.Generic.KeyNotFoundException: The given key 'amq.ctag-5j-__EPiXaD56-GGM3TCCA' was not present in the dictionary.
at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
at RabbitMQ.Client.Impl.ModelBase.HandleBasicCancelOk(String consumerTag)
at RabbitMQ.Client.Framing.Impl.Model.DispatchAsynchronous(IncomingCommand& cmd)
at RabbitMQ.Client.Impl.ModelBase.HandleCommand(IncomingCommand& cmd)
at RabbitMQ.Client.Impl.Session.HandleFrame(InboundFrame& frame)
at RabbitMQ.Client.Framing.Impl.Connection.MainLoopIteration()
at RabbitMQ.Client.Framing.Impl.Connection.MainLoop()

This error happens after a timeout waiting for the response to a BasicCancel. I haven't found the exact conditions to replicate this but looking at the code, the fix to this bug is straight forward.

I will send in a pull request with a fix for this issue.