MessageTypeMismatch represents user provided JSON not matching the message's type.

MethodNotFound represents a missing gRPC method in an upstream.

ServiceNotFound represents a missing gRPC service in an upstream, even though the service resolved to that upstream.

ServiceUnresolvable represents failure to resolve a gRPC service to its upstream FQDN.

Unknown represents an unknown internal error.

UpstreamConnFailure represents failure to connect to the upstream gRPC service.

VersionNotSpecified represents the user not specifying the upstream version when it is required.

VersionUndecidable represents there being multiple upstreams that match the specified (service, version) pair.

GRPCError is an error returned by gRPC upstream.

ProxyError represents internal errors.

Code represents type of internal error.