A unit of execution in a process. Can run methods on [Object]s simultaneously. The use of synchronization via [Mutex], [Semaphore] is advised if working with shared objects.
Returns true if this [Thread] is currently active. An active [Thread] cannot start work on a new method but can be joined with [method wait_to_finish].
Starts a new [Thread] that runs "method" on object "instance" with "userdata" passed as an argument. The "priority" of the [Thread] can be changed by passing a PRIORITY_* enum.
Returns OK on success, or ERR_CANT_CREATE on failure.
</description>
</method>
<methodname="wait_to_finish">
<returntype="Variant">
</return>
<description>
Joins the [Thread] and waits for it to finish. Returns what the method called returned.