...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Peek at the incoming data on the stream. Returns the number of bytes read, or 0 if an error occurred.
template< typename MutableBufferSequence> std::size_t peek( const MutableBufferSequence & buffers, boost::system::error_code & ec);