fix clippy warnings

src/rt/mod.rs

@@ -22,7 +22,8 @@ pub static RUNTIME: Lazy<Runtime> = Lazy::new(|| {
         .unwrap_or_else(|_| num_cpus::get())
         .max(1);
 
-    let thread_name = env::var("ASYNC_STD_THREAD_NAME").unwrap_or("async-std/runtime".to_string());
+    let thread_name =
+        env::var("ASYNC_STD_THREAD_NAME").unwrap_or_else(|_| "async-std/runtime".to_string());
 
     for _ in 0..thread_count {
         thread::Builder::new()

src/stream/stream/inspect.rs

@@ -41,9 +41,9 @@ where
         let mut this = self.project();
         let next = futures_core::ready!(this.stream.as_mut().poll_next(cx));
 
-        Poll::Ready(next.and_then(|x| {
+        Poll::Ready(next.map(|x| {
             (this.f)(&x);
-            Some(x)
+            x
         }))
     }
 }

src/task/builder.rs

@@ -41,7 +41,7 @@ impl Builder {
         #[cfg(not(target_os = "unknown"))]
         once_cell::sync::Lazy::force(&crate::rt::RUNTIME);
 
-        let tag = TaskLocalsWrapper::new(task.clone());
+        let tag = TaskLocalsWrapper::new(task);
 
         SupportTaskLocals { tag, future }
     }