1.000: C0 arrived [ ]
1.000: C0 service begin (by S0)
2.100: C1 arrived [ ]
2.100: C1 service begin (by S1)
3.100: C1 service done (by S1)
3.100: C1 departed
4.200: C2 arrived [ ]
4.200: C2 service begin (by S1)
5.000: C0 service done (by S0)
5.000: C0 departed
5.200: C2 service done (by S1)
5.200: C2 departed
