Extract interval method to make it available for recording metrics

remote/src/main/scala/org/apache/pekko/remote/PhiAccrualFailureDetector.scala

@@ -14,15 +14,13 @@
 package org.apache.pekko.remote
 
 import java.util.concurrent.atomic.AtomicReference
-
 import scala.annotation.tailrec
 import scala.collection.immutable
 import scala.concurrent.duration.Duration
 import scala.concurrent.duration.FiniteDuration
-
 import com.typesafe.config.Config
-
 import org.apache.pekko
+import pekko.annotation.InternalApi
 import pekko.event.EventStream
 import pekko.event.Logging
 import pekko.event.Logging.Warning
@@ -141,7 +139,6 @@ class PhiAccrualFailureDetector(
 
   @tailrec
   final override def heartbeat(): Unit = {
-
     val timestamp = clock()
     val oldState = state.get
 
@@ -155,15 +152,7 @@ class PhiAccrualFailureDetector(
         val interval = timestamp - latestTimestamp
         // don't use the first heartbeat after failure for the history, since a long pause will skew the stats
         if (isAvailable(timestamp)) {
-          if (interval >= (acceptableHeartbeatPauseMillis / 3 * 2) && eventStream.isDefined)
-            eventStream.get.publish(
-              Warning(
-                this.toString,
-                getClass,
-                s"heartbeat interval is growing too large for address $address: $interval millis",
-                Logging.emptyMDC,
-                RemoteLogMarker.failureDetectorGrowing(address)))
-          oldState.history :+ interval
+          recordInterval(interval)
         } else oldState.history
     }
 
@@ -174,6 +163,19 @@ class PhiAccrualFailureDetector(
     if (!state.compareAndSet(oldState, newState)) heartbeat() // recur
   }
 
+  @InternalApi
+  protected def recordInterval(interval: Long): HeartbeatHistory = {
+    if (interval >= (acceptableHeartbeatPauseMillis / 3 * 2) && eventStream.isDefined)
+      eventStream.get.publish(
+        Warning(
+          this.toString,
+          getClass,
+          s"heartbeat interval is growing too large for address $address: $interval millis",
+          Logging.emptyMDC,
+          RemoteLogMarker.failureDetectorGrowing(address)))
+    state.get.history :+ interval
+  }
+
   /**
    * The suspicion level of the accrual failure detector.
    *