hello from thread 1 (counter=0)
hello from thread 1 (counter=1)
hello from thread 2 (counter=2)
hello from thread 1 (counter=3)
hello from thread 2 (counter=4)
hello from thread 1 (counter=5)
hello from thread 2 (counter=6)
hello from thread 1 (counter=7)
hello from thread 2 (counter=8)
hello from thread 1 (counter=9)
hello from thread 2 (counter=10)
hello from thread 1 (counter=11)
hello from thread 2 (counter=12)
hello from thread 1 (counter=13)
hello from thread 2 (counter=14)
hello from thread 1 (counter=15)
hello from thread 2 (counter=16)
hello from thread 1 (counter=17)
hello from thread 2 (counter=18)
hello from thread 2 (counter=19)