"Wed, 21 Jan 1970 19:40:38"
Convert date and time to unixtime.
Another datetime format string at UTC
YYYYMMDD
19700121
Only TIME
19:40:38
General datetime
1970-01-21 19:40:38Z
For Database
1970-01-21 19:40:38
For HTTP1.1
Wed, 21 Jan 1970 19:40:38 GMT