On a resend response, when fetching the proto payload from the MSL, some
incorrect float math led to an off-by-one timestamp for some timestamps.
One example is the timestamp 1629210680140. When converting to a date:
1629210680140 / 1000.0 = 1629210680.1399999
Then when converting back to milliseconds:
Int(1629210680.1399999 * 1000.0) = 1629210680139
To fix this, the MSL now only operates with UInt64 millisecond
timestamps.
8bcf7d39ff