code: @SuppressWarnings("WeakerAccess")
    public UpdateInstanceRequest setDisplayName(@Nonnull String displayName) {
      Preconditions.checkNotNull(displayName);
      builder.getInstanceBuilder().setDisplayName(displayName);
      updateFieldMask(Instance.DISPLAY_NAME_FIELD_NUMBER);
  
      return this;
    }
docs: Changes the display name of the instance.