Values:
STATE_UNSPECIFIED (0):
The state is unknown. This is used for API
compatibility only and is not used by the
system.
PENDING (1):
The state was not sampled by the health
checks yet.
FAILED (2):
The source is available but might not be
usable yet due to invalid credentials or another
reason. The error message will contain further
details.
ACTIVE (3):
The source exists and its credentials were
verified.