Read some data from the handle.

template<
    typename MutableBufferSequence>
std::size_t read_some(
    const MutableBufferSequence & buffers);
  » more...

template<
    typename MutableBufferSequence>
std::size_t read_some(
    const MutableBufferSequence & buffers,
    asio::error_code & ec);
  » more...