diff --git a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/FakeApiService.java b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/FakeApiService.java
similarity index 96%
rename from google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/FakeApiService.java
rename to google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/FakeApiService.java
index 9be4e8e49..48998d7d9 100644
--- a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/FakeApiService.java
+++ b/google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/FakeApiService.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.google.cloud.pubsublite;
+package com.google.cloud.pubsublite.internal;
 
 import com.google.api.core.AbstractApiService;
 
diff --git a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/internal/SinglePartitionSubscriberTest.java b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/internal/SinglePartitionSubscriberTest.java
index 88b7b2f95..63a7eef24 100644
--- a/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/internal/SinglePartitionSubscriberTest.java
+++ b/google-cloud-pubsublite/src/test/java/com/google/cloud/pubsublite/cloudpubsub/internal/SinglePartitionSubscriberTest.java
@@ -27,7 +27,6 @@
 import com.google.api.core.ApiService.Listener;
 import com.google.cloud.pubsub.v1.AckReplyConsumer;
 import com.google.cloud.pubsub.v1.MessageReceiver;
-import com.google.cloud.pubsublite.FakeApiService;
 import com.google.cloud.pubsublite.Message;
 import com.google.cloud.pubsublite.MessageTransformer;
 import com.google.cloud.pubsublite.Offset;
@@ -35,6 +34,7 @@
 import com.google.cloud.pubsublite.cloudpubsub.FlowControlSettings;
 import com.google.cloud.pubsublite.cloudpubsub.MessageTransforms;
 import com.google.cloud.pubsublite.cloudpubsub.NackHandler;
+import com.google.cloud.pubsublite.internal.FakeApiService;
 import com.google.cloud.pubsublite.internal.StatusExceptionMatcher;
 import com.google.cloud.pubsublite.internal.wire.Subscriber;
 import com.google.cloud.pubsublite.internal.wire.SubscriberFactory;
diff --git a/pubsublite-beam-io/src/main/java/com/google/cloud/pubsublite/beam/PubsubLiteUnboundedReader.java b/pubsublite-beam-io/src/main/java/com/google/cloud/pubsublite/beam/PubsubLiteUnboundedReader.java
index e3affcdf3..9c9f410f4 100644
--- a/pubsublite-beam-io/src/main/java/com/google/cloud/pubsublite/beam/PubsubLiteUnboundedReader.java
+++ b/pubsublite-beam-io/src/main/java/com/google/cloud/pubsublite/beam/PubsubLiteUnboundedReader.java
@@ -23,6 +23,7 @@
 import com.google.cloud.pubsublite.SequencedMessage;
 import com.google.cloud.pubsublite.internal.CloseableMonitor;
 import com.google.cloud.pubsublite.internal.ExtractStatus;
+import com.google.cloud.pubsublite.internal.ProxyService;
 import com.google.cloud.pubsublite.internal.wire.Committer;
 import com.google.common.collect.ImmutableMap;
 import com.google.errorprone.annotations.concurrent.GuardedBy;
@@ -33,11 +34,14 @@
 import java.io.IOException;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.NoSuchElementException;
 import java.util.Optional;
 import java.util.Queue;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
 import org.apache.beam.sdk.io.UnboundedSource;
 import org.apache.beam.sdk.io.UnboundedSource.CheckpointMark;
 import org.apache.beam.sdk.io.UnboundedSource.UnboundedReader;
@@ -52,17 +56,51 @@ class PubsubLiteUnboundedReader extends UnboundedReader<SequencedMessage>
   @GuardedBy("monitor.monitor")
   private final ImmutableMap<Partition, SubscriberState> subscriberMap;
 
+  private final CommitterProxy committerProxy;
+
   @GuardedBy("monitor.monitor")
   private final Queue<PartitionedSequencedMessage> messages = new ArrayDeque<>();
 
   @GuardedBy("monitor.monitor")
   private Optional<StatusException> permanentError = Optional.empty();
 
+  private static class CommitterProxy extends ProxyService {
+    private final Consumer<StatusException> permanentErrorSetter;
+
+    CommitterProxy(
+        Collection<SubscriberState> states, Consumer<StatusException> permanentErrorSetter)
+        throws StatusException {
+      this.permanentErrorSetter = permanentErrorSetter;
+      addServices(states.stream().map(state -> state.committer).collect(Collectors.toList()));
+    }
+
+    @Override
+    protected void start() {}
+
+    @Override
+    protected void stop() {}
+
+    @Override
+    protected void handlePermanentError(StatusException error) {
+      permanentErrorSetter.accept(error);
+    }
+  }
+
   public PubsubLiteUnboundedReader(
       UnboundedSource<SequencedMessage, ?> source,
-      ImmutableMap<Partition, SubscriberState> subscriberMap) {
+      ImmutableMap<Partition, SubscriberState> subscriberMap)
+      throws StatusException {
     this.source = source;
     this.subscriberMap = subscriberMap;
+    this.committerProxy =
+        new CommitterProxy(
+            subscriberMap.values(),
+            error -> {
+              try (CloseableMonitor.Hold h = monitor.enter()) {
+                permanentError = Optional.of(permanentError.orElse(error));
+              }
+            });
+    this.committerProxy.startAsync().awaitRunning();
   }
 
   @Override
@@ -188,7 +226,6 @@ public Instant getCurrentTimestamp() throws NoSuchElementException {
   public void close() {
     try (CloseableMonitor.Hold h = monitor.enter()) {
       for (SubscriberState state : subscriberMap.values()) {
-        state.committer.stopAsync().awaitTerminated();
         try {
           state.subscriber.close();
         } catch (Exception e) {
@@ -196,6 +233,7 @@ public void close() {
         }
       }
     }
+    committerProxy.stopAsync().awaitTerminated();
   }
 
   @Override
diff --git a/pubsublite-beam-io/src/test/java/com/google/cloud/pubsublite/beam/PubsubLiteUnboundedReaderTest.java b/pubsublite-beam-io/src/test/java/com/google/cloud/pubsublite/beam/PubsubLiteUnboundedReaderTest.java
index 9812aaf94..80e237777 100644
--- a/pubsublite-beam-io/src/test/java/com/google/cloud/pubsublite/beam/PubsubLiteUnboundedReaderTest.java
+++ b/pubsublite-beam-io/src/test/java/com/google/cloud/pubsublite/beam/PubsubLiteUnboundedReaderTest.java
@@ -30,6 +30,7 @@
 import com.google.cloud.pubsublite.Partition;
 import com.google.cloud.pubsublite.SequencedMessage;
 import com.google.cloud.pubsublite.beam.PubsubLiteUnboundedReader.SubscriberState;
+import com.google.cloud.pubsublite.internal.FakeApiService;
 import com.google.cloud.pubsublite.internal.wire.Committer;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -48,6 +49,8 @@
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
+import org.mockito.MockitoAnnotations;
+import org.mockito.Spy;
 
 @RunWith(JUnit4.class)
 public class PubsubLiteUnboundedReaderTest {
@@ -57,8 +60,10 @@ public class PubsubLiteUnboundedReaderTest {
   @SuppressWarnings("unchecked")
   private final PullSubscriber<SequencedMessage> subscriber8 = mock(PullSubscriber.class);
 
-  private final Committer committer5 = mock(Committer.class);
-  private final Committer committer8 = mock(Committer.class);
+  abstract static class CommitterFakeService extends FakeApiService implements Committer {}
+
+  @Spy private CommitterFakeService committer5;
+  @Spy private CommitterFakeService committer8;
 
   @SuppressWarnings("unchecked")
   private final UnboundedSource<SequencedMessage, ?> source = mock(UnboundedSource.class);
@@ -78,6 +83,7 @@ private static Instant toInstant(Timestamp timestamp) {
   }
 
   public PubsubLiteUnboundedReaderTest() throws StatusException {
+    MockitoAnnotations.initMocks(this);
     SubscriberState state5 = new SubscriberState();
     state5.subscriber = subscriber5;
     state5.committer = committer5;
@@ -208,6 +214,5 @@ public void checkpointMarkFinalizeCommits() throws Exception {
     when(committer5.commitOffset(Offset.of(10))).thenReturn(ApiFutures.immediateFuture(null));
     mark.finalizeCheckpoint();
     verify(committer5).commitOffset(Offset.of(10));
-    verifyNoMoreInteractions(committer5, committer8);
   }
 }