public Builder setUpdateMask(com.google.protobuf.FieldMask value) {
      if (updateMaskBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        updateMask_ = value;
      } else {
        updateMaskBuilder_.setMessage(value);
      }
      bitField0_ |= 0x00000001;
      onChanged();
      return this;
    }
<pre>
Optional. The list of fields to be updated on the instance. At least one
field must be specified.
</pre>

<code>.google.protobuf.FieldMask update_mask = 1 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-valkey/proto-google-cloud-valkey-v1beta/src/main/java/com/google/cloud/memorystore/v1beta/UpdateInstanceRequest.java