code: @BetaApi
    public final Operation updateBackendBucket(
        String backendBucket, BackendBucket backendBucketResource, List<String> fieldMask) {
  
      UpdateBackendBucketHttpRequest request =
          UpdateBackendBucketHttpRequest.newBuilder()
              .setBackendBucket(backendBucket)
              .setBackendBucketResource(backendBucketResource)
              .addAllFieldMask(fieldMask)
              .build();
      return updateBackendBucket(request);
    }
docs: Updates the specified BackendBucket resource with the data included in the request.
  
  <p>Sample code:
  
  <pre><code>
  try (BackendBucketClient backendBucketClient = BackendBucketClient.create()) {
  ProjectGlobalBackendBucketName backendBucket = ProjectGlobalBackendBucketName.of("[PROJECT]", "[BACKEND_BUCKET]");
  BackendBucket backendBucketResource = BackendBucket.newBuilder().build();
  List&lt;String&gt; fieldMask = new ArrayList&lt;&gt;();
  Operation response = backendBucketClient.updateBackendBucket(backendBucket.toString(), backendBucketResource, fieldMask);
  }
  </code></pre>
  
  @param backendBucket Name of the BackendBucket resource to update.
  @param backendBucketResource A BackendBucket resource. This resource defines a Cloud Storage
  bucket.
  @param fieldMask The fields that should be serialized (even if they have empty values). If the
  containing message object has a non-null fieldmask, then all the fields in the field mask
  (and only those fields in the field mask) will be serialized. If the containing object does
  not have a fieldmask, then only non-empty fields will be serialized.
  @throws com.google.api.gax.rpc.ApiException if the remote call fails