"Wed, 21 Jan 1970 00:18:44"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700121
Only TIME
00:18:44
General datetime
1970-01-21 00:18:44Z
For Database
1970-01-21 00:18:44
For HTTP1.1
Wed, 21 Jan 1970 00:18:44 GMT