Allow checkpointing from the Ready state.

[nataren]

Hello there:

First, _thanks a lot_ for writing this library.

Second, I am trying to use it, and I am performing accumulation of records in my workers (IRecordProcess implementation), and after some period of time, out of band, I fire a function that finally processes the accumulated records and stores them, and it is at that point that I know the _SequenceId_ of the last record that I am 100% has been successfully processed and _checkpoint_ right there. But, since that function fires out of band (meaning, it is not happening on the ProcessRecords method invocation), the state in which the state machine can be anything, in particular I noticed that it would be in the _Ready_ state, therefore when I try to checkpoint at that moment I am getting failures, since it is an invalid transition.

So, I was wondering if it would reasonable to be able to _Checkpoint_ when the state machine is on the _Ready_ state, that would allow me to persist my data after I have accumulated enough records or recurrently after certain period of time, without having to wait to be tickled by the _ProcessRecords_ call.

One such stacktrace looked like this:

System.Collections.TimeRecurrentAccumulator`2[[Amazon.Kinesis.ClientLibrary.Record, AmazonKinesisClientLibrary,ion=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Amazon.Kinesis.ClientLibrary.Record, AmazonKinesisClientLibrary, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]((null)) - RecurringAccumulator handler failed on.Kinesis.ClientLibrary.MalformedActionException: trigger BeginCheckpoint is invalid for state Ready

Amazon.Kinesis.ClientLibrary.DefaultKclProcess.<ConfigureStateMachine>b__0 (State state, Trigger trigger) [0x00000] in <filename unknown>:0 Stateless.StateMachine`2[Amazon.Kinesis.ClientLibrary.DefaultKclProcess+State,Amazon.Kinesis.ClientLibrary.DefaultKclProcess+Trigger].InternalFire (Trigger trigger, System.Object[] args) [0x00000] in <filename unknown>:0

Stateless.StateMachine`2[Amazon.Kinesis.ClientLibrary.DefaultKclProcess+State,Amazon.Kinesis.ClientLibrary.DefaultKclProcess+Trigger].Fire (Trigger trigger) [0x00000] in <filename unknown>:0

Amazon.Kinesis.ClientLibrary.DefaultKclProcess+InternalCheckpointer.Checkpoint (System.String sequenceNumber, Amazon.Kinesis.ClientLibrary.CheckpointErrorHandler errorHandler) [0x00000] in <filename unknown>:0

Amazon.Kinesis.ClientLibrary.Checkpointer.Checkpoint (Amazon.Kinesis.ClientLibrary.Record record, Amazon.Kinesis.ClientLibrary.CheckpointErrorHandler errorHandler) [0x00000] in <filename unknown>:0

What do you think?

Regards
césar