internal val UNICODE_BOMS =
  Options.of(
    // UTF-8.
    "efbbbf".decodeHex(),
    // UTF-16BE.
    "feff".decodeHex(),
    // UTF-32LE.
    "fffe0000".decodeHex(),
    // UTF-16LE.
    "fffe".decodeHex(),
    // UTF-32BE.
    "0000feff".decodeHex(),
  )

/**
 * Returns an array containing only elements found in this array and also in [other]. The returned
 * elements are in the same order as in this.

        assertEquals("FF", Hexdump.toHexString(data2, 0, 2)); // 2 chars = 1 byte
        assertEquals("FFF", Hexdump.toHexString(data2, 0, 3)); // 3 chars = 1.5 bytes (rounds up to 2)
        assertEquals("FFFE", Hexdump.toHexString(data2, 0, 4)); // 4 chars = 2 bytes
        assertEquals("FFFE80", Hexdump.toHexString(data2, 0, 6)); // 6 chars = 3 bytes
        assertEquals("FFFE807F", Hexdump.toHexString(data2, 0, 8)); // 8 chars = 4 bytes

    assertFalse(InetAddresses.isMappedIPv4Address("::ffff"));
    assertFalse(InetAddresses.isMappedIPv4Address("::ffff:0"));
    assertFalse(InetAddresses.isMappedIPv4Address("::fffe:0:0"));
    assertFalse(InetAddresses.isMappedIPv4Address("::1:ffff:0:0"));
    assertFalse(InetAddresses.isMappedIPv4Address("foo"));
    assertFalse(InetAddresses.isMappedIPv4Address("192.0.2.1"));
  }

FFFC          ; disallowed                             # 2.1  OBJECT REPLACEMENT CHARACTER
FFFD          ; disallowed                             # 1.1  REPLACEMENT CHARACTER
FFFE..FFFF    ; disallowed                             # 1.1  <noncharacter-FFFE>..<noncharacter-FFFF>
10000..1000B  ; valid                                  # 4.0  LINEAR B SYLLABLE B008 A..LINEAR B SYLLABLE B046 JE