phpstan: stub out the iterable bullshit with pthreads

this isn't a perfect fix, but it's better than it whining about all the things.

phpstan.neon.dist

@@ -18,6 +18,8 @@ parameters:
 	dynamicConstantNames:
 		- pocketmine\IS_DEVELOPMENT_BUILD
 		- pocketmine\DEBUG
+	stubFiles:
+		- tests/phpstan/stubs/pthreads.stub
 	reportUnmatchedIgnoredErrors: false #no other way to silence platform-specific non-warnings
 	checkMissingIterableValueType: false #TODO: pthreads Threaded base for too many things, fix this later
 	ignoreErrors:

tests/phpstan/stubs/pthreads.stub

@@ -0,0 +1,6 @@
+<?php
+
+/**
+ * @implements \Traversable<array-key, mixed>
+ */
+class Threaded implements \Traversable{}