Narrow down onVolumeChanged to only volume changed's

runescape-api/src/main/java/net/runelite/rs/api/RSClient.java

@@ -1117,4 +1117,7 @@ public interface RSClient extends RSGameShell, Client
 	 */
 	@Import("Login_promptCredentials")
 	void promptCredentials(boolean clearPass);
+
+	@Import("VarpDefinition_get")
+	RSVarpDefinition getVarpDefinition(int id);
 }

runescape-api/src/main/java/net/runelite/rs/api/RSVarpDefinition.java

@@ -0,0 +1,9 @@
+package net.runelite.rs.api;
+
+import net.runelite.mapping.Import;
+
+public interface RSVarpDefinition extends RSDualNode
+{
+	@Import("type")
+	int getType();
+}