startRecordingFd method
Same as startRecording, but writes through an already-open file
descriptor instead of a path — for destinations with no plain
filesystem path available, e.g. Android's public Downloads folder via
MediaStore (see core_rtlsdr's
RecordingController.startRecordingToDownloads).
Implementation
@override
int startRecordingFd(int fd) {
final status = _consumeStatus();
if (status == 0) {
_recording = true;
recordingFd = fd;
}
return status;
}