feat(lib): add upgrade feature

Cargo.toml

@@ -30,12 +30,12 @@ httparse = "1.8"
 h2 = { version = "0.3.9", optional = true }
 itoa = "1"
 pin-project-lite = "0.2.4"
-tokio = { version = "1", features = ["sync"] }
 
 # Optional
 
 httpdate = { version = "1.0", optional = true }
 libc = { version = "0.2", optional = true }
+tokio = { version = "1", features = ["sync"], optional = true }
 tracing = { version = "0.1", default-features = false, features = ["std"], optional = true }
 want = { version = "0.3", optional = true }
 
@@ -74,13 +74,16 @@ full = [
 ]
 
 # HTTP versions
-http1 = []
-http2 = ["dep:h2"]
+http1 = ["upgrade"]
+http2 = ["upgrade", "dep:h2"]
 
 # Client/Server
 client = ["dep:want"]
 server = ["dep:httpdate"]
 
+# HTTP Upgrades
+upgrade = ["dep:tokio"]
+
 # C-API support (currently unstable (no semver))
 ffi = ["dep:libc", "dep:http-body-util"]
 

src/lib.rs

@@ -49,8 +49,10 @@
 //! - `http2`: Enables HTTP/2 support.
 //! - `client`: Enables the HTTP `client`.
 //! - `server`: Enables the HTTP `server`.
+//! - `upgrade`: Enables [HTTP Upgrades].
 //!
 //! [feature flags]: https://doc.rust-lang.org/cargo/reference/manifest.html#the-features-section
+//! [Http Upgrades]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Protocol_upgrade_mechanism
 //!
 //! # Unstable Features
 //! hyper includes a set of unstable optional features that can be enabled through the use of a
@@ -65,6 +67,7 @@
 //! RUSTFLAGS="--cfg hyper_unstable_tracing" cargo rustc --features client,http1,http2,tracing --crate-type cdylib
 //!```
 //! [configuration flag]: https://doc.rust-lang.org/reference/conditional-compilation.html
+
 #[doc(hidden)]
 pub use http;
 
@@ -93,7 +96,6 @@ pub mod ext;
 mod mock;
 pub mod rt;
 pub mod service;
-pub mod upgrade;
 
 #[cfg(feature = "ffi")]
 #[cfg_attr(docsrs, doc(cfg(all(feature = "ffi", hyper_unstable_ffi))))]
@@ -115,3 +117,9 @@ cfg_feature! {
 
     pub mod server;
 }
+
+cfg_feature! {
+    #![feature = "upgrade"]
+
+    pub mod upgrade;
+}