protected IReadOnlyCollection <string> Handle(CapabilitiesQuery command) => _componentState.SupportedCapabilities();
protected Task <string> Handle(CapabilitiesQuery message) { return(Task.FromResult("xxx")); }
protected IReadOnlyCollection <string> Handle(CapabilitiesQuery command) => _componentState.SupportedCapabilities();
protected Task <string> Handle(CapabilitiesQuery message) { return(Task.FromResult("xxx")); }