1.000: C0 arrived [ ]
1.000: C0 service begin (by S0)
1.100: C1 arrived [ ]
1.100: C1 service begin (by S1)
2.000: C0 service done (by S0)
2.000: C0 departed
2.100: C1 service done (by S1)
2.100: C1 departed
2.200: C2 arrived [ ]
2.200: C2 service begin (by S0)
2.300: C3 arrived [ ]
2.300: C3 service begin (by S1)
3.200: C2 service done (by S0)
3.200: C2 departed
3.300: C3 service done (by S1)
3.300: C3 departed