Client should implement methods in this class to allow for consistent, global handling of route-specific error types,
as well as general network errors. Normally, error handling is done on a request-by-request basis.
However, it is convenient to handle some error behavior consistently, regardless of the request or the endpoint.
For implementing global error handling for general networking errors like an auth error, `createNetworkErrorCallback`
should be implemented. For implementing global error handling for route-specific errors, the
`createRouteErrorCallback` should be implemented.