[libvirt] qemuDomainMonitorCommand

Hi, I've been looking at the qemuDomainMonitorCommand interface and I see a few issues with it. The current interface can take a JSON string and return a JSON string but it only works for successful commands. I'd like to hook this interface up to libqmp but it would mean dropping all of the error messages. Errors are extremely important because certain workflows require parsing specific error output (like changing a device with an encrypted disk) in the normal execution path. Additionally, there's no way to get QMP events. With QMP events, it's important to expose the timestamp and tag fields too. Is there a reason the raw QMP session wasn't exposed? With registered events, we should be able to distinguish events meant for libvirt with events registered by QMP passthrough so perhaps we can also expose events in a new interface? Regards, Anthony Liguori