participant "Client 1" as C1
participant "Client 2" as C2
participant "Reactive Web App" as RWS
participant "Backend" as S3
C1 -> RWS: POST
activate C1
activate RWS
RWS -> S3: Async POST
deactivate RWS
C2 -> RWS: POST
activate C2
activate RWS
RWS -> S3: Async POST
deactivate RWS
S3 --> RWS: Async Result
activate RWS
RWS -->C2: Result
deactivate RWS
deactivate C2
// First file EOF
S3 --> RWS: Async Result
activate RWS
RWS -->C1: Result
deactivate RWS
deactivate C1