fn buffers_drop_unused(&self) {
        let mut pool = self.released.take();
        pool.retain(|b| {
            if b.in_use.get() {
                return true;
            }
            b.destroy();
            false
        });
        self.released.replace(pool);
    }
// attempt to release unused buffers.
attempt to release unused buffers.
attempt to release unused buffers .
fn buffers_drop_unused(&self) {
        let mut pool = self.released.take();
        pool.retain(|b| {
            if b.in_use.get() {
                return true;
            }
            b.destroy();
            false
        });
        self.released.replace(pool);
    }
fn buffers_drop_unused ( & self ) { let mut pool = self . released . take ( ) ; pool . retain ( | b | { if b . in_use . get ( ) { return true ; } b . destroy ( ) ; false } ) ; self . released . replace ( pool ) ; }
attempt to release unused buffers.
attempt to release unused buffers .
&self
&self