Fixesspring-projects/spring-integration-aws#71
It isn't correct to call `converter.convert()` in the
`KinesisMessageHandler` if `payload` is already `ByteBuffer` or `byte[]`
On the other hand an application might be interested in the `byte[]`
payload on the consumer side.
The `KinesisMessageDrivenChannelAdapter` must be able to produce
`byte[]` `payload` without any conversion.
* Add logic into `KinesisMessageHandler` to check the `payload` type
before calling `converter.convert()`
* Allow to configure `converter` to `null` for the
`KinesisMessageDrivenChannelAdapter`.
The body of the consumed record is presented in the `payload` as is -
`byte[]`
* Add JavaDoc to the `KinesisMessageHandler.setConverter()`
4a0201f29d