.addEqualityGroup(
            MediaType.create("text", "plain").withParameter("a", "value"),
            MediaType.create("text", "plain").withParameter("A", "value"))
        .addEqualityGroup(
            MediaType.create("text", "plain").withParameter("a", "VALUE"),
            MediaType.create("text", "plain").withParameter("A", "VALUE"))
        .addEqualityGroup(
            MediaType.create("text", "plain")

        .addEqualityGroup(
            MediaType.create("text", "plain").withParameter("a", "value"),
            MediaType.create("text", "plain").withParameter("A", "value"))
        .addEqualityGroup(
            MediaType.create("text", "plain").withParameter("a", "VALUE"),
            MediaType.create("text", "plain").withParameter("A", "VALUE"))
        .addEqualityGroup(
            MediaType.create("text", "plain")

   * #withParameters(String, Iterable)}. Prefer {@link #withCharset} for setting the {@code charset}
   * parameter when using a {@link Charset} object.
   *
   * @throws IllegalArgumentException if either {@code attribute} or {@code value} is invalid
   */
  public MediaType withParameter(String attribute, String value) {
    return withParameters(attribute, ImmutableSet.of(value));
  }

  /**