Remove retain_mut crate (#11926)

* Remove retain_mut crate

* Remove reain_mut crate from babe-consensus

substrate/client/consensus/babe/Cargo.toml

@@ -26,7 +26,6 @@ num-rational = "0.2.2"
 num-traits = "0.2.8"
 parking_lot = "0.12.0"
 rand = "0.7.2"
-retain_mut = "0.1.4"
 schnorrkel = { version = "0.9.1", features = ["preaudit_deprecated"] }
 serde = { version = "1.0.136", features = ["derive"] }
 thiserror = "1.0"

substrate/client/consensus/babe/src/lib.rs

@@ -87,7 +87,6 @@ use futures::{
 use log::{debug, info, log, trace, warn};
 use parking_lot::Mutex;
 use prometheus_endpoint::Registry;
-use retain_mut::RetainMut;
 use schnorrkel::SignatureError;
 
 use sc_client_api::{
@@ -835,17 +834,16 @@ where
 		slot: Slot,
 		epoch_descriptor: &ViableEpochDescriptor<B::Hash, NumberFor<B>, Epoch>,
 	) {
-		RetainMut::retain_mut(&mut *self.slot_notification_sinks.lock(), |sink| {
-			match sink.try_send((slot, epoch_descriptor.clone())) {
-				Ok(()) => true,
-				Err(e) =>
-					if e.is_full() {
-						warn!(target: "babe", "Trying to notify a slot but the channel is full");
-						true
-					} else {
-						false
-					},
-			}
+		let sinks = &mut self.slot_notification_sinks.lock();
+		sinks.retain_mut(|sink| match sink.try_send((slot, epoch_descriptor.clone())) {
+			Ok(()) => true,
+			Err(e) =>
+				if e.is_full() {
+					warn!(target: "babe", "Trying to notify a slot but the channel is full");
+					true
+				} else {
+					false
+				},
 		});
 	}