Values:
STATE_UNSPECIFIED (0):
Invalid.
PENDING (1):
Request is submitted, but training has not
started yet. The model may remain in this state
until there is enough capacity to start
training.
SUCCEEDED (2):
The training has succeeded.
FAILED (3):
The training has succeeded.
CANCELLED (4):
The training has been cancelled.
CANCELLING (5):
The training is in cancelling state.
TRAINING (6):
Custom model is training.