Return Profiler old interval from setInterval (#2354)

Author: jackshirazi

inferred-spans/src/main/java/io/opentelemetry/contrib/inferredspans/InferredSpans.java

@@ -42,10 +42,12 @@ public static boolean isEnabled() {
    *
    * @param interval the new profiler interval
    */
-  public static void setProfilerInterval(Duration interval) {
+  @Nullable
+  public static Duration setProfilerInterval(Duration interval) {
     InferredSpansProcessor p = instance;
     if (p != null) {
-      p.setProfilerInterval(interval);
+      return p.setProfilerInterval(interval);
     }
+    return null;
   }
 }

inferred-spans/src/main/java/io/opentelemetry/contrib/inferredspans/InferredSpansProcessor.java

@@ -57,9 +57,10 @@ public class InferredSpansProcessor implements SpanProcessor {
     }
   }
 
-  public void setProfilerInterval(Duration interval) {
-    config.setProfilerInterval(interval);
+  public Duration setProfilerInterval(Duration interval) {
+    Duration oldInterval = config.setProfilerInterval(interval);
     profiler.reschedule();
+    return oldInterval;
   }
 
   public static InferredSpansProcessorBuilder builder() {

inferred-spans/src/main/java/io/opentelemetry/contrib/inferredspans/internal/InferredSpansConfiguration.java

@@ -84,8 +84,10 @@ public Duration getProfilingInterval() {
     return profilerInterval;
   }
 
-  public void setProfilerInterval(Duration profilerInterval) {
+  public Duration setProfilerInterval(Duration profilerInterval) {
+    Duration oldInterval = this.profilerInterval;
     this.profilerInterval = profilerInterval;
+    return oldInterval;
   }
 
   public Duration getProfilingDuration() {