Remove FnService for now

Seems like it may not show up that often in practice, so let's cut down on scope
and concepts.

src/lib.rs

@@ -210,47 +210,6 @@ impl<S: NewService + ?Sized> NewService for Rc<S> {
     }
 }
 
-/// A service implemented by a closure.
-pub struct FnService<F, R> {
-    f: F,
-    _ty: PhantomData<fn() -> R>, // don't impose Sync on R
-}
-
-/// Returns a `Service` backed by the given closure.
-pub fn fn_service<F, R, S>(f: F) -> FnService<F, R>
-    where F: Fn(R) -> S,
-          S: IntoFuture,
-{
-    FnService::new(f)
-}
-
-impl<F, R, S> FnService<F, R>
-    where F: Fn(R) -> S,
-          S: IntoFuture,
-{
-    /// Create and return a new `FnService` backed by the given function.
-    pub fn new(f: F) -> FnService<F, R> {
-        FnService {
-            f: f,
-            _ty: PhantomData,
-        }
-    }
-}
-
-impl<F, R, S> Service for FnService<F, R>
-    where F: Fn(R) -> S,
-          S: IntoFuture
-{
-    type Request = R;
-    type Response = S::Item;
-    type Error = S::Error;
-    type Future = S::Future;
-
-    fn call(&self, req: R) -> Self::Future {
-        (self.f)(req).into_future()
-    }
-}
-
 impl<S: Service + ?Sized> Service for Box<S> {
     type Request = S::Request;
     type Response = S::Response;