// |timeStamp| is a DOMHighResTimeStamp in the time coordinate system of performance.now().
void didReceiveMIDIData(unsigned portIndex, const unsigned char* data, size_t length, double timeStamp);
// |timeStamp| is a DOMHighResTimeStamp in the time coordinate system of performance.now().
void didReceiveMIDIData(unsigned portIndex, const unsigned char* data, size_t length, double timeStamp);