diff --git a/tower-util/src/lib.rs b/tower-util/src/lib.rs
index 2237e7d..67d472a 100644
--- a/tower-util/src/lib.rs
+++ b/tower-util/src/lib.rs
@@ -31,6 +31,8 @@ pub use crate::{
 #[cfg(feature = "call-all")]
 pub use crate::call_all::{CallAll, CallAllUnordered};
 
+type Error = Box<dyn std::error::Error + Send + Sync>;
+
 pub mod error {
     //! Error types
 
@@ -44,3 +46,39 @@ pub mod future {
     pub use crate::either::future as either;
     pub use crate::optional::future as optional;
 }
+
+/// An extension trait for `Service`s that provides a variety of convenient
+/// adapters
+pub trait ServiceExt<Request>: tower_service::Service<Request> {
+    /// A future yielding the service when it is ready to accept a request.
+    fn ready(&mut self) -> Ready<'_, Self, Request>
+    where
+        Self: Sized,
+    {
+        Ready::new(self)
+    }
+
+    /// Consume this `Service`, calling with the providing request once it is ready.
+    fn oneshot(self, req: Request) -> Oneshot<Self, Request>
+    where
+        Self: Sized,
+    {
+        Oneshot::new(self, req)
+    }
+
+    /// Process all requests from the given `Stream`, and produce a `Stream` of their responses.
+    ///
+    /// This is essentially `Stream<Item = Request>` + `Self` => `Stream<Item = Response>`. See the
+    /// documentation for [`CallAll`](struct.CallAll.html) for details.
+    #[cfg(feature = "call-all")]
+    fn call_all<S>(self, reqs: S) -> CallAll<Self, S>
+    where
+        Self: Sized,
+        Self::Error: Into<Error>,
+        S: futures_core::Stream<Item = Request>,
+    {
+        CallAll::new(self, reqs)
+    }
+}
+
+impl<T: ?Sized, Request> ServiceExt<Request> for T where T: tower_service::Service<Request> {}
diff --git a/tower/src/util.rs b/tower/src/util.rs
index 8eea103..87cf6c8 100644
--- a/tower/src/util.rs
+++ b/tower/src/util.rs
@@ -1,44 +1,6 @@
 //! Combinators for working with `Service`s
 
-use futures_core::Stream;
-use tower_service::Service;
 pub use tower_util::{
-    BoxService, CallAll, CallAllUnordered, Either, Oneshot, Optional, Ready, UnsyncBoxService,
+    BoxService, CallAll, CallAllUnordered, Either, Oneshot, Optional, Ready, ServiceExt,
+    UnsyncBoxService,
 };
-
-impl<T: ?Sized, Request> ServiceExt<Request> for T where T: Service<Request> {}
-
-type Error = Box<dyn std::error::Error + Send + Sync>;
-
-/// An extension trait for `Service`s that provides a variety of convenient
-/// adapters
-pub trait ServiceExt<Request>: Service<Request> {
-    /// A future yielding the service when it is ready to accept a request.
-    fn ready(&mut self) -> Ready<'_, Self, Request>
-    where
-        Self: Sized,
-    {
-        Ready::new(self)
-    }
-
-    /// Consume this `Service`, calling with the providing request once it is ready.
-    fn oneshot(self, req: Request) -> Oneshot<Self, Request>
-    where
-        Self: Sized,
-    {
-        Oneshot::new(self, req)
-    }
-
-    /// Process all requests from the given `Stream`, and produce a `Stream` of their responses.
-    ///
-    /// This is essentially `Stream<Item = Request>` + `Self` => `Stream<Item = Response>`. See the
-    /// documentation for [`CallAll`](struct.CallAll.html) for details.
-    fn call_all<S>(self, reqs: S) -> CallAll<Self, S>
-    where
-        Self: Sized,
-        Self::Error: Into<Error>,
-        S: Stream<Item = Request>,
-    {
-        CallAll::new(self, reqs)
-    }
-}