feat: track chat socket latency

chat/src/main/java/com/github/twitch4j/chat/ITwitchChat.java

@@ -79,6 +79,11 @@ default boolean sendMessage(String channel, String message, @Unofficial String n
     @Override
     void close();
 
+    /**
+     * @return the most recently measured round-trip latency for the socket(s) in milliseconds, or -1 if unknown
+     */
+    long getLatency();
+
     /**
      * @return cached mappings of channel ids to names
      */

chat/src/main/java/com/github/twitch4j/chat/TwitchChat.java

@@ -53,6 +53,7 @@
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Consumer;
 
@@ -237,6 +238,14 @@ public class TwitchChat implements ITwitchChat {
      */
     private final int wsPingPeriod;
 
+    /**
+     * Tracks the timestamp of the last outbound ping
+     */
+    protected final AtomicLong lastPing = new AtomicLong();
+
+    @Getter
+    protected volatile long latency = -1L;
+
     /**
      * Cache of recent number of join attempts for each channel
      */
@@ -625,6 +634,23 @@ public void onDisconnected(WebSocket websocket,
                         log.info("Disconnected from Twitch IRC (WebSocket)!");
                     }
                 }
+
+                @Override
+                public void onFrameSent(WebSocket websocket, WebSocketFrame frame) {
+                    if (frame != null && frame.isPingFrame()) {
+                        lastPing.compareAndSet(0L, System.currentTimeMillis());
+                    }
+                }
+
+                @Override
+                public void onPongFrame(WebSocket websocket, WebSocketFrame frame) {
+                    final long last = lastPing.getAndSet(0L);
+                    if (last > 0) {
+                        latency = System.currentTimeMillis() - last;
+                        log.trace("TwitchChat: Round-trip socket latency recorded at {} ms.", latency);
+                    }
+                }
+
             });
 
         } catch (Exception ex) {

chat/src/main/java/com/github/twitch4j/chat/TwitchChatConnectionPool.java

@@ -278,6 +278,20 @@ protected void disposeConnection(TwitchChat connection) {
         connection.close();
     }
 
+    @Override
+    public long getLatency() {
+        long sum = 0;
+        int count = 0;
+        for (TwitchChat connection : getConnections()) {
+            final long latency = connection.getLatency();
+            if (latency > 0) {
+                sum += latency;
+                count++;
+            }
+        }
+        return count > 0 ? sum / count : -1L;
+    }
+
     /**
      * Note: this map does not dynamically update unlike {@link TwitchChat#getChannelIdToChannelName()}
      * <p>