Timestamps created in EventBuilder are incorrect

[watsonjj]

SSDAQ/ssdaq/receivers/readout_assembler.py

Line 31 in 7c70571

cpu_time = datetime.utcnow()

SSDAQ/ssdaq/receivers/readout_assembler.py

Line 255 in 7c70571

cpu_time_s = int(r_cpu_time.timestamp())

Using datetime.datetime.utcnow().timestamp() results in an incorrect unix time if your timezone is not UTC.

See https://docs.python.org/3/library/datetime.html#datetime.datetime.utcnow and https://bugs.python.org/issue33293.

Correct approach to get seconds from epoch (UTC/unix) using the datetime package is datetime.datetime.now(datetime.timezone.utc).timestamp().

Existing SS data therefore contain a timestamp that if you assume is unix time, is two hours earlier than the true unix time.

[watsonjj]

Analysis up to this point has correctly accounted for this. But this has the potential to be very confusing in the future.