Allocations

The heap allocations of another JVM on this machine, read with the JDK alone: the Attach API starts the JVM's local management agent (or finds it started), and its ThreadMXBean answers the bytes all its threads, the finished ones included, allocated since it started (JDK 21). connect attaches once, before the measured phase (B.O-2: starting the agent costs the target a moment); each Reader.read after is one call over the open connection.