I'm not concerned about my own completion handlers. The handlers in Asio's composed operations is the problem. And I have no way to wrap those in strands.
<<In the case of composed asynchronous operations, such as async_read() or async_read_until(), if a completion handler goes through a strand, then all intermediate handlers should also go through the same strand. This is needed to ensure thread safe access for any objects that are shared between the caller and the composed operation (in the case of async_read() it's the socket, which the caller can close() to cancel the operation). This is done by having hook functions for all intermediate handlers which forward the calls to the customisable hook associated with the final handler>> http://www.boost.org/doc/libs/1_45_0/doc/html/boost_asio/overview/core/stran...