[tcgc] Descuss: shall we allow Optional property in clientInitialization Model

[chunyu3]

Shall we allow ClientIntialization Model contains optional property? as following:

namespace MyCustomizations;
model MyServiceClientOptions {
   id: string;
  blobName?: string;
}

@@clientInitialization(MyService, MyServiceClientOptions)

If so,
What's the rule to bump a operation parameter to client via @clientInitialization

• scenario1: the parameter are all required in all operations

namespace MyService;

op upload(blobName: string): void;
op download(blobName: string): void;

// client.tsp
namespace MyCustomizations;
model MyServiceClientOptions {
  blobName: string;
}

@@clientInitialization(MyService, MyServiceClientOptions)

Then the bumped parameter blobName should be required property in ClientIntialization Model

• scenario2: the parameter are all optional in all operations

namespace MyService;

op upload(blobName: string): void;
op download(blobName?: string): void;

// client.tsp
namespace MyCustomizations;
model MyServiceClientOptions {
  blobName: string;
  blobID?: string
}

Then the bumped parameter blobName should be optional property in ClientIntialization Model

• scenario 3: optional in one operation, required in another one

namespace MyService;

op upload(blobName: string): void;
op download(blobName?: string): void;

// client.tsp
namespace MyCustomizations;
model MyServiceClientOptions {
  blobName: string;
  blobID?: string
}

@@clientInitialization(MyService, MyServiceClientOptions)

We should not allow this. Define a Linter rule to avoid this.