...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Cancel any asynchronous operations that are waiting on the resolver.
void cancel();
This function forces the completion of any pending asynchronous operations
on the host resolver. The handler for each cancelled operation will be
invoked with the boost::asio::error::operation_aborted
error code.