The init function doesn't seem all that useful and makes the interface a
bit more complicated, so drop it.
Also addresses a race condition that can happen with tagged thread
startup when the proxy tries to talk to a tagged thread but the tagged
thread hasn't connected yet (which then aborts the proxy because it
assumes workers are always routable).
This renames the class to make it clearer what it does, and drops the
.name attribute from it so that it can cheaply be passed around. This
then means it can be cheaply passed by value (using std::optionals)
rather than by pointer when specifying a thread.
This adds to ability to have lokimq manage specific threads to which
jobs (individual, batch jobs, batch completions, or timers) can be
directed to. This allows dedicating a thread to some slow or
thread-unsafe action where you can dump jobs to the tagged thread as
a method of lockless job queuing.
Jason Rhinelander