(PECL pthreads >= 2.0.0)
When the start method of a Thread is invoked, the run method code will be executed in separate Thread, asynchronously.
After the run method is executed the Thread will exit immediately, it will be joined with the creating Thread at the approriate time.
Relying on the engine to determine when a Thread should join may cause undesirable behaviour; the programmer should be explicit, where possible.