Represents how the data source supports data auto refresh.
Values:
DATA_REFRESH_TYPE_UNSPECIFIED (0):
The data source won't support data auto
refresh, which is default value.
SLIDING_WINDOW (1):
The data source supports data auto refresh,
and runs will be scheduled for the past few
days. Does not allow custom values to be set for
each transfer config.
CUSTOM_SLIDING_WINDOW (2):
The data source supports data auto refresh,
and runs will be scheduled for the past few
days. Allows custom values to be set for each
transfer config.
