Builds a v2 header, for the tests and the live probe: IPv4 or IPv6 PROXY
or LOCAL, extra TLVs, and a CRC32C when asked.
Parameters
Optionaloptions: BuildOptions
command ('LOCAL' for a LOCAL header), source and
destination addresses and ports, tlvs, crc32c, and
declaredLength to write a length other than the true one
Builds a v2 header, for the tests and the live probe: IPv4 or IPv6 PROXY or LOCAL, extra TLVs, and a CRC32C when asked.