This new function is an extension of the original msgpack_unpacker_next()
where it now adds third argument to store the number of parsed bytes for
the returned buffer upon a MSGPACK_UNPACK_SUCCESS case.
This is useful for cases where the caller needs to optimize memory usage
in the original buffer,s so upon success retrieval of the object, it can
later deprecate the already 'parsed' bytes.
For more details about the origins of this function please refer to the
following issue on github:
https://github.com/msgpack/msgpack-c/issues/514
Signed-off-by: Eduardo Silva <eduardo@treasure-data.com>
Eduardo Silva