Rules for AIP-151, covering long-running operations.
|lro-metadata-reachable||LRO metadata messages must be reachable.|
|lro-metadata-type||LRO methods must have a metadata type.|
|lro-response-reachable||LRO response messages must be reachable.|
|lro-response-type||LRO methods must have a response type.|
|operation-info||LRO methods must include an `operation_info` annotation.|
|response-unary||Long-running operations must not use streaming.|
Note: Because AIPs sometimes cover topics that have some overlap, some rules related to long-running operations may be included in the rules for other AIPs.