* show up in ASN.1 streams to also indicate the end of SEQUENCE, SET or other constructed
     * value.
     */
    private val END_OF_DATA =
      DerHeader(
        tagClass = DerHeader.TAG_CLASS_UNIVERSAL,
        tag = DerHeader.TAG_END_OF_CONTENTS,
        constructed = false,
        length = -1L,
      )
  }

  /** A source that keeps track of how many bytes it's consumed. */