MethodsClientImpl is difficult to subclass

[joeltoby]

MethodsClientImpl implements over 130 API methods from the MethodsClient interface. Each of these methods in turn invokes one of three private doPost... methods.

I would like to extend MethodsClientImpl within my project to add some custom rate limiting, but this would require overriding each of the 130+ methods (as the private doPost... methods cannot be overridden).

Changing the access modifiers on the three doPost methods from private to protected would make it much easier for clients to write custom MethodsClient implementations.

[joeltoby]

I actually solved my custom Rate Limiting issue a different way, but I still think this change would make extending the MethodsClient easier for other clients.