Merge branch 'main' into receivers-mtls

Author: lalitb

rust/otap-dataflow/crates/otap/src/accessory/slots.rs

@@ -81,6 +81,31 @@ impl<UData> State<UData> {
         Some((key, ures))
     }
 
+    /// Modify user data in a slot (if key is valid).
+    #[must_use]
+    pub fn get_mut(&mut self, key: Key) -> Option<&mut UData> {
+        self.slots.get_mut(key)
+    }
+
+    /// Modify user data in a slot with a function. Return true for
+    /// the slot to stay alive.
+    #[must_use]
+    pub fn mutate<F>(&mut self, key: Key, mut f: F) -> Option<UData>
+    where
+        F: FnMut(&mut UData) -> bool,
+    {
+        if self
+            .slots
+            .get_mut(key)
+            .map(|value| !f(value))
+            .unwrap_or(false)
+        {
+            self.slots.remove(key)
+        } else {
+            None
+        }
+    }
+
     /// Take user data from a slot (if key is valid).
     #[must_use]
     pub fn take(&mut self, key: Key) -> Option<UData> {
@@ -89,7 +114,7 @@ impl<UData> State<UData> {
 
     /// Take and drop the user data (if key is valid).
     pub fn cancel(&mut self, key: Key) {
-        let _ = self.take(key);
+        _ = self.take(key);
     }
 }