NetworkRequest: add a SetTimeout method.

headers/os/net/NetworkRequest.h

@@ -24,6 +24,7 @@ public:
 									const char* protocolName);
 
 	virtual	status_t			Stop();
+	virtual status_t			SetTimeout(bigtime_t timeout);
 
 protected:
 			bool 				_ResolveHostName(BString host, uint16_t port);

headers/os/net/UrlRequest.h

@@ -28,6 +28,7 @@ public:
 	virtual status_t				Pause();
 	virtual status_t				Resume();
 	virtual	status_t				Stop();
+	virtual status_t				SetTimeout(bigtime_t timeout) {}
 
 	// URL protocol parameters modification
 			status_t				SetUrl(const BUrl& url);