Any contains an arbitrary serialized protocol buffer message along with a
URL that describes the type of the serialized message.
A Duration represents a signed, fixed-length span of time represented
as a count of seconds and fractions of seconds at nanosecond
resolution. It is independent of any calendar and concepts like “day”
or “month”. It is related to Timestamp in that the difference between
two Timestamp values is a Duration and it can be added or subtracted
from a Timestamp. Range is approximately +-10,000 years.
A Timestamp represents a point in time independent of any time zone or local
calendar, encoded as a count of seconds and fractions of seconds at
nanosecond resolution. The count is relative to an epoch at UTC midnight on
January 1, 1970, in the proleptic Gregorian calendar which extends the
Gregorian calendar backwards to year one.