2.1.1.2. Stream Flags

        The first byte of Stream Flags is always a null byte. In the
        future, this byte may be used to indicate a new Stream version
        or other Stream properties.

        The second byte of Stream Flags is a bit field:

            Bit(s)  Mask  Description
             0-3    0x0F  Type of Check (see Section 3.4):
                              ID    Size      Check name
                              0x00   0 bytes  None
                              0x01   4 bytes  CRC32
                              0x02   4 bytes  (Reserved)
                              0x03   4 bytes  (Reserved)
                              0x04   8 bytes  CRC64
                              0x05   8 bytes  (Reserved)
                              0x06   8 bytes  (Reserved)
                              0x07  16 bytes  (Reserved)
                              0x08  16 bytes  (Reserved)
                              0x09  16 bytes  (Reserved)
                              0x0A  32 bytes  SHA-256
                              0x0B  32 bytes  (Reserved)
                              0x0C  32 bytes  (Reserved)
                              0x0D  64 bytes  (Reserved)
                              0x0E  64 bytes  (Reserved)
                              0x0F  64 bytes  (Reserved)
             4-7    0xF0  Reserved for future use; MUST be zero for now.