Clients must implement this interface in order to instantiate objects of type CRemConCoreApiTarget. This interface passes incoming commands from RemCon to the client. In order to minimise the number of virtual functions the client has to implement, (a) they aren't pure, and (b) most commands are presented via 'Command' with an operation ID. Commands which are associated with command-specific data come instead through specific methods, e.g. 'Play', which comes with a play speed. Incoming commands are given to client via the MRemConCoreApiTargetObserver mixin. Having received a command, the client is obliged to send a response. A client can only have one send outstanding at any time. If commands come in quickly, the client is responsible for queueing its responses to them. Note that each command delivered to a target involves memory allocated in the server s heap, which is only released on client closure or when a response is sent.