# |(mask - 1bit)|(payload length - 7 bits)
# As specified, if the payload length is 126 or 127
# The next 16 or 64 bits contain an extended payload length
# |(mask - 1bit)|(payload length - 7 bits)
# As specified, if the payload length is 126 or 127
# The next 16 or 64 bits contain an extended payload length