0 init
1 init
2 init

0 irecv 1 0 2000
1 isend 0 0 2000
2 irecv 1 1 3000

0 irecv 2 2 3000
1 isend 2 1 3000
2 isend 0 2 3000

0 waitall
1 waitall
2 waitall

0 finalize
1 finalize
2 finalize