...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
The type of buffer returned when dereferencing an iterator.
using value_type = see-below;
If every buffer sequence in the view is a MutableBufferSequence,
then value_type
will be
net::mutable_buffer
. Otherwise, value_type
will be net::const_buffer
.