Get rid of poll pending hack, more threads in example file

examples/lua/lots_of_threads.luau

@@ -2,7 +2,7 @@
 --!nolint UnknownGlobal
 
 local NUM_BATCHES = 10
-local NUM_THREADS = 10_000
+local NUM_THREADS = 100_000
 
 print(`Spawning {NUM_BATCHES * NUM_THREADS} threads split into {NUM_BATCHES} batches\n`)
 

lib/runtime.rs

@@ -6,10 +6,8 @@ use smol::prelude::*;
 use smol::{block_on, Executor, LocalExecutor};
 
 use super::{
-    error_callback::ThreadErrorCallback,
-    queue::ThreadQueue,
-    traits::IntoLuaThread,
-    util::{is_poll_pending, LuaThreadOrFunction},
+    error_callback::ThreadErrorCallback, queue::ThreadQueue, traits::IntoLuaThread,
+    util::LuaThreadOrFunction,
 };
 
 pub struct Runtime<'lua> {
@@ -112,7 +110,10 @@ impl<'lua> Runtime<'lua> {
                     // and only if we get the pending value back we can spawn to async executor
                     match thread.resume::<_, LuaValue>(args.clone()) {
                         Ok(v) => {
-                            if is_poll_pending(&v) {
+                            if v.as_light_userdata()
+                                .map(|l| l == Lua::poll_pending())
+                                .unwrap_or_default()
+                            {
                                 spawn_queue.push(lua, &thread, args)?;
                             }
                         }

lib/util.rs

@@ -1,42 +1,5 @@
-use std::cell::OnceCell;
-
 use mlua::prelude::*;
 
-use crate::IntoLuaThread;
-
-thread_local! {
-    static POLL_PENDING: OnceCell<LuaLightUserData> = OnceCell::new();
-}
-
-fn get_poll_pending(lua: &Lua) -> LuaResult<LuaLightUserData> {
-    let yielder_fn = lua.create_async_function(|_, ()| async move {
-        smol::future::yield_now().await;
-        Ok(())
-    })?;
-
-    yielder_fn
-        .into_lua_thread(lua)?
-        .resume::<_, LuaLightUserData>(())
-}
-
-#[inline]
-pub(crate) fn is_poll_pending(value: &LuaValue) -> bool {
-    // TODO: Replace with Lua::poll_pending() when it's available
-
-    let pp = POLL_PENDING.with(|cell| {
-        *cell.get_or_init(|| {
-            let lua = Lua::new().into_static();
-            let pending = get_poll_pending(lua).unwrap();
-            // SAFETY: We only use the Lua state for the lifetime of this function,
-            // and the "poll pending" light userdata / pointer is completely static.
-            drop(unsafe { Lua::from_static(lua) });
-            pending
-        })
-    });
-
-    matches!(value, LuaValue::LightUserData(u) if u == &pp)
-}
-
 /**
     Wrapper struct to accept either a Lua thread or a Lua function as function argument.