Add ThrottlingSignaler class to the Java SDK (#36119)

* Add ThrottlingSignaler class to the Java SDK

* Update sdks/java/io/components/src/main/java/org/apache/beam/sdk/io/components/throttling/ThrottlingSignaler.java

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* set default namespace

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: jrmccluskey

sdks/java/io/components/src/main/java/org/apache/beam/sdk/io/components/throttling/ThrottlingSignaler.java

@@ -0,0 +1,46 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.io.components.throttling;
+
+import org.apache.beam.sdk.metrics.Counter;
+import org.apache.beam.sdk.metrics.Metrics;
+/**
+ * The ThrottlingSignaler is a utility class for IOs to signal to the runner
+ * that a process is being throttled, preventing autoscaling. This is primarily
+ * used when making calls to a remote service where quotas and rate limiting
+ * are reasonable considerations.
+ */
+public class ThrottlingSignaler {
+  private final Counter throttleCounter;
+
+  public ThrottlingSignaler(String namespace) {
+    this.throttleCounter = Metrics.counter(namespace, Metrics.THROTTLE_TIME_COUNTER_NAME);
+  }
+
+  public ThrottlingSignaler() {
+    this(Metrics.THROTTLE_TIME_NAMESPACE);
+  }
+
+  /**
+   * Signal that a transform has been throttled for an amount of time
+   * represented in milliseconds.
+   */
+  public void signalThrottling(long milliseconds) {
+    throttleCounter.inc(milliseconds);
+  }
+}