observe Hydration Data Max Timestamp
Returns Flowable that emits UNIX-timestamp of last hydration data.
If there is no data then 0 will be emitted.
Return
Flowable that emits UNIX-timestamp of last hydration data
Returns Flowable that emits UNIX-timestamp of last hydration data.
If there is no data then 0 will be emitted.
Flowable that emits UNIX-timestamp of last hydration data