/// Trait implemented by a `Box`ed callable that can be executed once.
pubtraitBoxedFnOnce{/// The type returned by the callable when called.
typeOutput;/// Calls the boxed callable and returns the result.
fncall_box(self: Box<Self>)->Self::Output;}/// Blanket implementation of `BoxedFnOnce` for `FnOnce`.
impl<T, F:FnOnce()-> T> BoxedFnOnce forF{typeOutput= T;#[inline]fncall_box(self: Box<F>)->Self::Output{(*self)()}}