#### buffered_read_stream::peek

Peek at the incoming data on the stream. Returns the number of bytes read. Throws an exception on failure.

    template<
        typename MutableBufferSequence>
    std::size_t peek(
        const MutableBufferSequence & buffers);

    template<
        typename MutableBufferSequence>
    std::size_t peek(
        const MutableBufferSequence & buffers,
        asio::error_code & ec);