#### buffered_write_stream::async_read_some

Start an asynchronous read. The buffer into which the data will be read must be valid for the lifetime of the asynchronous operation.

    template<
        typename MutableBufferSequence,
        typename ReadHandler = DEFAULT>
    DEDUCED async_read_some(
        const MutableBufferSequence & buffers,
        ReadHandler && handler = DEFAULT);

###### Completion Signature

    void(asio::error_code, std::size_t)