Out of memory error while using Http2 Async Controller

[ck-singh]

Using HTTP2 Async controller with JMeter 5.5 and jdk-11.0.18.10-hotspot. The script runs perfect on a low user load, but when ran at a slightly higher user load (25 users) the test fails with Out of memory errors. On closer look it was found that the heap memory footprint of each of the "org.apache.jmeter.threads.JMeterThread @ 0xef0c1b70" class is consuming 27 MBs during execution (as shown in attached screenshot).

Also observed following error in jmeter.log:-
"INFO o.e.j.i.AbstractConnection: Failure while notifying listener org.eclipse.jetty.http2.client.HTTP2ClientConnectionFactory$ConnectionListener@4cc6cc75 java.lang.OutOfMemoryError: Java heap space"

[ck-singh]

All listeners and assertions had already been disabled in the script and the test is being run in non-gui mode.