Method block_on

src/thread_pool.rs:695–704

(&'static self, future: F)

        //
        // * If `Self` is `!Send`, its `Runnable` must be used and dropped on
        //   the original thread.
        //
        //   The second clause of the `Spawn<M>::spawn` safety contract requires
        //   the caller to confine `scheduler` to the original thread, so
        //   `execute_runnable`, and by extension the `Runnable`, only
        //   ever run there.
        //
        //   A `JobRef` has no `Drop` impl, so a `JobRef` that is never executed
        //   leaks its `Runnable` instead of dropping it. The `Runnable` is thus
        //   only ever dropped inside `execute_runnable` which, again, only runs
        //   on the correct original.
        //
        // * If `Self` is `!'static`, borrowed variables must outlive its