* String#equalsIgnoreCase}). However in almost all cases that ASCII strings are used, the author
   * probably wanted the behavior provided by this method rather than the subtle and sometimes
   * surprising behavior of {@code toUpperCase()} and {@code toLowerCase()}.
   *
   * @since 16.0
   */
  public static boolean equalsIgnoreCase(CharSequence s1, CharSequence s2) {

 *     "Unexpected bill status: %s", bill.status());
 * }
 *
 * <h3>Comparison to alternatives</h3>
 *
 * <p><b>Note:</b> In some cases the differences explained below can be subtle. When it's unclear
 * which approach to use, <b>don't worry</b> too much about it; just pick something that seems
 * reasonable and it will be fine.
 *
 * <ul>

   * to use {@code Predicates.<Object>in()}.
   *
   * <p>You may prefer to use a method reference (e.g., {@code target::contains}) instead of this
   * method. However, there are some subtle considerations:
   *
   * <ul>
   *   <li>The {@link Predicate} returned by this method is {@link Serializable}.
   *   <li>The {@link Predicate} returned by this method catches {@link ClassCastException} and

    this because it only occurs if you have proxy configured and you share a connection pool among
    multiple `OkHttpClient` instances.

    This particularly-subtle bug was caused by us assigning each `OkHttpClient` instance its own
    `NullProxySelector` when an explicit proxy is configured. But we don't share connections when
    the proxy selectors are different. Ugh!