ErrorToExceptionHandler currently prevents these from appearing by turning them into exceptions, but this won't always be the case.
For example, in the future we may not want to turn ALL types of E_* errors into exceptions (e.g. E_DEPRECATED).
there's no need for the worker specialization here (isShutdown and shutdown are aliased to isJoined and join respectively), and the unstacking is not really desirable either as we previously learned with AsyncPool.
Despite the comments, there doesn't seem to be an obvious reason for these to be copy-pasted. Perhaps there was some legacy reason for this with legacy pthreads.
In fact, it looks likely that quit() will probably be able to be traitified too.
until now, any thread crash would show as a generic crash since we aren't able to get the trace from the crashed thread directly. This uses some dirty tricks to export a partially serialized stack trace to the main thread, where it can be written into a crashdump.
This enables us to see proper crash information for async tasks in the crash archive (finally!!!) as well as being able to capture RakLib errors properly.
the only use for this class is to facilitate random runtime plugin loading, and it's not complete even for that purpose.
Since nothing but PM uses pocketmine/classloader anyway, it doesn't make sense to have it outside the core. As with LogPthreads, it's just adding more maintenance work.
