$ java --enable-preview -Xmx6g ScopedValueVsThreadLocalMemory 500000      (JDK 25)
threads per scenario: 500000, 5 bound values each, forked via StructuredTaskScope
CHECK ok   : every one of 1000 subtasks read all 5 scoped values correctly
CHECK ok   : every one of 1000 subtasks read all 5 inherited ThreadLocal values correctly
CHECK ok   : every one of 500000 subtasks read all 5 scoped values correctly
ScopedValue:  500000 live subtasks, 5 bound values each, heap delta = 531.8 MB (1115 bytes/thread)
CHECK ok   : every one of 500000 subtasks read all 5 inherited ThreadLocal values correctly
ThreadLocal:  500000 live subtasks, 5 inherited values each, heap delta = 546.1 MB (1145 bytes/thread)
ThreadLocal used 1.0x the heap ScopedValue used, for holding the identical 5 values live on 500000 threads
exit=0