code: public final void modifyPushConfig(String subscription, PushConfig pushConfig) {
  
      ModifyPushConfigRequest request =
          ModifyPushConfigRequest.newBuilder()
              .setSubscription(subscription)
              .setPushConfig(pushConfig)
              .build();
      modifyPushConfig(request);
    }
docs: Modifies the `PushConfig` for a specified subscription.
  
  <p>This may be used to change a push subscription to a pull one (signified by an empty
  `PushConfig`) or vice versa, or change the endpoint URL and other attributes of a push
  subscription. Messages will accumulate for delivery continuously through the call regardless of
  changes to the `PushConfig`.
  
  <p>Sample code:
  
  <pre><code>
  try (SubscriptionAdminClient subscriptionAdminClient = SubscriptionAdminClient.create()) {
  ProjectSubscriptionName subscription = ProjectSubscriptionName.of("[PROJECT]", "[SUBSCRIPTION]");
  PushConfig pushConfig = PushConfig.newBuilder().build();
  subscriptionAdminClient.modifyPushConfig(subscription.toString(), pushConfig);
  }
  </code></pre>
  
  @param subscription The name of the subscription. Format is
  `projects/{project}/subscriptions/{sub}`.
  @param pushConfig The push configuration for future deliveries.
  <p>An empty `pushConfig` indicates that the Pub/Sub system should stop pushing messages
  from the given subscription and allow messages to be pulled and acknowledged - effectively
  pausing the subscription if `Pull` or `StreamingPull` is not called.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails