thread_spawn

Spawns a new thread named thread_name running thread_func with user_data passed to it.

thread_func must return a [class@Dex.Future].

If this function is called from a thread that is not running a [class@Dex.Scheduler] then the default scheduler will be used to call user_data_destroy.

If the resulting [class@Dex.Future] has not resolved or rejected, then the same scheduler used to call user_data_destroy will be used to propagate the result to the caller.

Parameters:

thread_name	the name for the thread
thread_func	the function to call on a thread
user_data	closure data for thread_func
user_data_destroy	callback to free user_data which will be called on the same thread calling this function.

Returns:

a [class@Dex.Future] that resolves or rejects the value or error returned from thread_func as a [class@Dex.Future].