You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mod.rs
    path of file: ./repos/phaser/phaser/vendor/futures-util/src/stream/futures_unordered
    
    the code of the file until where you have to start completion: //! An unbounded set of futures.
//!
//! This module is only available when
    
    pub fn iter_pin_mut(mut self: Pin<&mut Self>) -> IterPinMut<'_, Fut> {
        // `head_all` can be accessed directly and we don't need to spin on
        // `Task::next_all` since we have exclusive access to the set.
        let task = *self.head_all.get_mut();
        let len = if task.is_null() { 0 } else { unsafe { *(*task).len_all.get() } };

        IterPinMut { task, len, _marker: PhantomData }
    }