Optimize hot paths

Identify and optimize frequently executed code paths to improve performance. Hot paths have a significant impact on overall application performance.

Key strategies include:

1. Use inline attributes for small functions: Add #[inline] to small functions called in performance-critical sections:

   #[doc(hidden)]
   #[inline]  // Added to improve inlining in hot paths
   pub fn has_budget_remaining() -> bool {
    // Function body
   }
   

2. Implement early returns: Avoid unnecessary computation when a quick result is possible:

   pub fn poll_next_many(/* params */) -> Poll<usize> {
    if limit == 0 || self.entries.is_empty() {
        return Poll::Ready(0);  // Early return avoids unnecessary work
    }
    // Remaining logic
   }
   

3. Reduce lock contention: Store frequently accessed constant data outside of locks:

   // Instead of obtaining a lock to read a constant value
   fn get_shard_size(&self) -> u32 {
    // Store this as a field instead of reading through a lock
    self.shard_count  // Direct field access instead of lock.read().len()
   }
   

4. Minimize atomic operations: Evaluate whether atomic operations in hot paths can be avoided or optimized.

5. Avoid generic code bloat: Extract non-generic operations into separate functions to prevent monomorphization bloat, especially in frequently used code:

   // Instead of using map with generic logic
   impl::spawn_child_with(&mut self.std, with)  // Direct function call
   

Each optimization may seem small individually, but they can significantly improve performance when applied to code that executes thousands or millions of times.