split -server and -tls msrv and raise to 1.52 (#398)

actix-server/src/accept.rs

@@ -81,14 +81,9 @@ struct Accept {
 }
 
 /// Array of u128 with every bit as marker for a worker handle's availability.
+#[derive(Debug, Default)]
 struct Availability([u128; 4]);
 
-impl Default for Availability {
-    fn default() -> Self {
-        Self([0; 4])
-    }
-}
-
 impl Availability {
     /// Check if any worker handle is available
     #[inline(always)]

actix-server/src/worker.rs

@@ -181,6 +181,7 @@ impl WorkerHandleAccept {
 /// Held by [ServerBuilder](crate::builder::ServerBuilder).
 #[derive(Debug)]
 pub(crate) struct WorkerHandleServer {
+    #[allow(dead_code)]
     idx: usize,
     tx: UnboundedSender<Stop>,
 }