*: Remove warnings when compiling without default features (#2692)

* Remove unused import in rendezvous tests

* Expand uds-transport conditionals to include features

In case neither the tokio nor the async-std feature is defined,
this file needs to be empty to avoid unused code warnings.

Co-authored-by: Max Inden <mail@max-inden.de>

protocols/rendezvous/tests/harness.rs

@@ -22,7 +22,6 @@ use async_trait::async_trait;
 use futures::stream::FusedStream;
 use futures::StreamExt;
 use futures::{future, Stream};
-use libp2p::core::muxing::StreamMuxerBox;
 use libp2p::core::transport::upgrade::Version;
 use libp2p::core::transport::MemoryTransport;
 use libp2p::core::upgrade::SelectUpgrade;

transports/uds/src/lib.rs

@@ -31,7 +31,11 @@
 //! The `UdsConfig` structs implements the `Transport` trait of the `core` library. See the
 //! documentation of `core` and of libp2p in general to learn how to use the `Transport` trait.
 
-#![cfg(all(unix, not(target_os = "emscripten")))]
+#![cfg(all(
+    unix,
+    not(target_os = "emscripten"),
+    any(feature = "tokio", feature = "async-std")
+))]
 #![cfg_attr(docsrs, doc(cfg(all(unix, not(target_os = "emscripten")))))]
 
 use futures::stream::BoxStream;