Fix imports; rust stable in CI

.drone.yml

@@ -17,7 +17,7 @@ steps:
       - git checkout $DRONE_COMMIT
 
   - name: style
-    image: rustlang/rust:nightly
+    image: rust:1.58-buster
     environment:
       CARGO_HOME: /drone/cargo
     commands:
@@ -28,7 +28,7 @@ steps:
       - cargo clippy --example basalt --all-features -- --deny warnings
 
   - name: build
-    image: rustlang/rust:nightly
+    image: rust:1.58-buster
     environment:
       CARGO_HOME: /drone/cargo
     commands:
@@ -41,7 +41,7 @@ steps:
       - cargo build --example basalt --features "basalt"
 
   - name: test
-    image: rustlang/rust:nightly
+    image: rust:1.58-buster
     environment:
       CARGO_HOME: /drone/cargo
     commands:

Cargo.toml

@@ -17,7 +17,7 @@ name = "netapp"
 [features]
 default = []
 basalt = ["lru", "rand"]
-telemetry = ["opentelemetry", "opentelemetry-contrib"]
+telemetry = ["opentelemetry", "opentelemetry-contrib", "rand"]
 
 [dependencies]
 futures = "0.3.17"

src/server.rs

@@ -7,7 +7,7 @@ use log::{debug, trace};
 
 #[cfg(feature = "telemetry")]
 use opentelemetry::{
-	trace::{FutureExt, Span, SpanKind, TraceContextExt, TraceId, Tracer},
+	trace::{FutureExt, SpanKind, TraceContextExt, TraceId, Tracer},
 	Context, KeyValue,
 };
 #[cfg(feature = "telemetry")]