task_join()
Syntax
task_join(task)
Waits for the task completion and returns its computed value. If the task has
already finished returns it immediately. Unless taking the task value directly,
i.e. via task_value, this operation is blocking. Since Minecraft has a
limitation that all world access operations have to be performed on the main
game thread in the off-tick time, joining any tasks that use Minecraft API from
the main thread would mean automatic lock, so joining from the main thread is
not allowed. Join tasks from other threads, if you really need to, or
communicate asynchronously with the task via globals or function data /
arguments to monitor its progress, communicate, get partial results, or signal
termination.