feat(client): add 1.0 compatible client conn API (#3155)

This patch backports client/conn/http1 and http2 modules from 1.0 to
ease transition. It allows code still using 0.14.x to switch to the
per-version Connection types available in 1.0.

Closes #3053 

Co-authored-by: KOVACS Tamas <[email protected]>

Author: 2 people

src/client/conn.rs

@@ -54,6 +54,11 @@
 //! # }
 //! ```
 
+#[cfg(all(feature = "backports", feature = "http1"))]
+pub mod http1;
+#[cfg(all(feature = "backports", feature = "http2"))]
+pub mod http2;
+
 use std::error::Error as StdError;
 use std::fmt;
 #[cfg(not(all(feature = "http1", feature = "http2")))]