gRPC: RST_STREAM(NO_ERROR) handling (ticket #1792). As per https://tools.ietf.org/html/rfc7540#section-8.1, : A server can send a complete response prior to the client : sending an entire request if the response does not depend on : any portion of the request that has not been sent and : received. When this is true, a server MAY request that the : client abort transmission of a request without error by : sending a RST_STREAM with an error code of NO_ERROR after : sending a complete response (i.e., a frame with the : END_STREAM flag). Clients MUST NOT discard responses as a : result of receiving such a RST_STREAM, though clients can : always discard responses at their discretion for other : reasons. Previously, RST_STREAM(NO_ERROR) received from upstream after a frame with the END_STREAM flag was incorrectly treated as an error. Now, a single RST_STREAM(NO_ERROR) is properly handled. This fixes problems observed with modern grpc-c [1], as well as with the Go gRPC module. [1] https://github.com/grpc/grpc/pull/1661