Unix Timestamp clarification in Provider API

[asadowns]

Time fields like start_time, end_time, and route timestamp currently specify their type as Unix Timestamp. An example from route timestamp is 1531007628.3774529.

This leaves it open to interpretation and confusion what the correct format is.

GBFS spec specifies for instance

Integer POSIX timestamp

and provides an example 1434054678 or epoch seconds.

So using the example from route it should be either 1531007628 for epoch seconds. Or, if greater precision is required epoch milliseconds would be 531007628377.

In either case it would be good to clarify what the preferred format for providing time is. If you let me know your preference, I'll put out a PR.

[thekaveman]

Great point @asadowns, some clarification would be useful here. I personally like the GBFS approach; keeping it as integer, epoch seconds. I can't think of why millisecond precision would be necessary for provider. Yet on the agency side, I can see where that might matter more.

And ideally, as elsewhere, the two should be aligned where possible.

Edit: recalling that @ian-r-rose expressed interest in relaxing the integer restriction over on CityofSantaMonica/mds-provider#4 (comment).