@Contract(pure = true)
  public static int indexOfIgnoreCase(@NotNull String where, char what, int fromIndex) {
    int sourceCount = where.length();
    for (int i = Math.max(fromIndex, 0); i < sourceCount; i++) {
      if (charsEqualIgnoreCase(where.charAt(i), what)) {
        return i;
      }
    }

    return -1;
  }
@Contract(pure = true)
  public static int indexOfIgnoreCase(@NotNull String where, char what, int fromIndex)