-XX:StartFlightRecording=dumponexit=true,disk=false doesn't work

If you start a recording with

java -XX:StartFlightRecording=dumponexit=true,disk=false ...

you will get a recording file, but the size will be 0. This doesn't happen if you supply a filename.

Starting an in-memory recording and dump it when the JVM exits is a common use case of JFR. The reason this hasn't been noticed before is probably because most people either supply a filename or they don't set disk=false as this parameter is new for -XX:StartFlightRecording with JDK 9.

I = H (loss of data)
L= L/M (common use case for JFR)
W=L (supply a filename)

H(L/M)L -> P2/P3