v0.1009.0

v0.1009.0

New features

• Added encode_contiguous and encode_length_delimited_contiguous APIs to the
  Message trait which use the encode_fast prepend-encoding code path but
  measure the size first to always produce a contiguous buffer.
• Added into_vec(self) to ReverseBuffer complete with a non-copying
  optimization when the buffer is full and contiguous, such as when it is
  produced by Message::encode_contiguous.