refactor(lib): Import tracing macros per-module

Instead of one #[macro_use] at the crate root.

src/proto/h1/encode.rs

@@ -3,6 +3,7 @@ use std::io::IoSlice;
 
 use bytes::buf::{Chain, Take};
 use bytes::Buf;
+use tracing::trace;
 
 use super::io::WriteBuf;