Investigate memory usage with JfrUnit

[bric3]

Gunnar Morling started a project there to characteristics using JFR events : https://github.com/gunnarmorling/jfrunit

  repositories {
      jcenter()
+     maven { setUrl("https://jitpack.io") }
  }

  dependencies {
+     testImplementation("com.github.gunnarmorling:jfrunit:main-SNAPSHOT")
  }