private final boolean plusForSpace;

  /**
   * An array of flags where for any {@code char c} if {@code safeOctets[c]} is true then {@code c}
   * should remain unmodified in the output. If {@code c >= safeOctets.length} then it should be
   * escaped.
   */
  private final boolean[] safeOctets;

  /**
   * Constructs a percent escaper with the specified safe characters and optional handling of the
   * space character.