@Contract(pure = true)
  public static int indexOf(byte @NotNull [] array, byte @NotNull [] pattern, int startIndex) {
    for (int i = startIndex; i <= array.length - pattern.length; i++) {
      if (startsWith(array, i, pattern)) {
        return i;
      }
    }
    return -1;
  }
@Contract(pure = true)
  public static int indexOf(byte @NotNull [] array, byte @NotNull [] pattern, int startIndex)