Create a new non-modifiable buffer that represents the given string.
template< typename Elem, typename Traits, typename Allocator> mutable_buffers_1 buffer( std::basic_string< Elem, Traits, Allocator > & data, std::size_t max_size_in_bytes);
value equivalent to:
mutable_buffers_1( data.size() ? &data : 0, min(data.size() * sizeof(Elem), max_size_in_bytes));
The buffer is invalidated by any non-const operation called on the given string object.