Having an additional Client has added some confusion (https://github.com/harlow/kinesis-consumer/issues/45) on how to provide a
custom kinesis client. Allowing `WithClient` to accept a Kinesis client
it cleans up the interface.
Major changes:
* Remove the Client wrapper; prefer using kinesis client directly
* Change `ScanError` to `ScanStatus` as the return value isn't necessarily an error
Note: these are breaking changes, if you need last stable release please see here: https://github.com/harlow/kinesis-consumer/releases/tag/v0.2.0
The Checkpoint functionality is an important part of the library and
previously it wasn't obvious that the Consumer was defaulting to Redis
for this functionality.
* Add Checkpoint as required param for new consumer
Major changes:
* Remove intermediate batching of kinesis records
* Call the callback func with each record
* Use functional options for config
https://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis
Minor changes:
* update README messaging about Kinesis -> Firehose functionality
* remove unused buffer and emitter code
