Need to handle failure cases in API calls

[mjyeaney]

In the example below, we aren't handling the failure scenario for remote API calls (which can fail). Need to provide explicit handling of these cases - should likely extract a unit-of-work pattern here to help with testing.

CustomVisionParallelScoring/src/ModelScoring.py

Lines 49 to 59 in b597ce2

	response = await httpclient.AsyncHTTPClient().fetch(
	method="POST",
	body=test_data.read(),
	request=apiUrl,
	headers={
	"Prediction-Key": self.predictionKey,
	"Content-Type": "application/octet-stream"
	},
	raise_error=False
	)
	results = json.loads(response.body.decode())