TimestampFromFloat64 returns a Timestamp equal to the given float64, assuming it too is a unix timestamp.

TimestampFromInt64 returns a Timestamp equal to the given int64, assuming it too is a unix timestamp.

TimestampFromString attempts to parse the string as a float64, and then passes that into TimestampFromFloat64, returning the result.

TimestampNow is simply a wrapper around time.Now which returns a Timestamp.

Timestamp is a wrapper around time.Time which adds methods to marshal and unmarshal the value as a unix timestamp instead of a formatted string.