[MetricsAdvisor] Consider making constructor of complex types parameterless

[kinelski]

Take DataFeed as an example.

DataFeed takes multiple complex types as arguments in its constructor: DataFeedSchema, DataFeedIngestionSettings, DataFeedGranularity. Users need to know which objects are required and create them before calling the constructor:

var source = new AzureEventHubsDataSource(...);
var schema = new DataFeedSchema(new List<DataFeedMetric>() { metric1, metric2 });
var ingestionSettings = new DataFeedIngestionSettings(DateTimeOffset.UtcNow);
var granularity = new DataFeedGranularity(DataFeedGranularityType.Daily);

var dataFeed = new DataFeed("my data feed", source, granularity, schema, ingestionSettings);

Consider making the constructor parameterless. Users need to rely on thrown exceptions to figure out which properties are required:

var dataFeed = new DataFeed();

adminClient.CreateDataFeed(dataFeed); // throw: "name is required"

Next attempt:

var dataFeed = new DataFeed();
dataFeed.Name = "my data feed";

adminClient.CreateDataFeed(dataFeed); // throw: "data source is required"

We could:

• Check that required properties are present in the client side before sending the request.
• Let the service handle the error.