@startuml

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participant "E20 main thread" as main
participant "tdm thread" as sub

== an asynchronous event ==
sub <-- : an asynchronous event
activate sub
sub -> sub: calling thread callbacks in tdm-thread
activate sub
deactivate sub
main <-- sub: sending an asynchronous event
deactivate sub
activate main
main -> main: calling thread callbacks in main-thread
activate main
deactivate main
deactivate main

== a synchronous event ==
sub <-- : a synchronous event
activate sub
sub -> sub: calling thread callbacks in tdm-thread
activate sub
deactivate sub
sub --> main: sending a synchronous event
activate main
sub -> sub: pthread_cond_wait
activate sub
main -> main: calling thread callbacks in main-thread
activate main
deactivate main
main --> sub: pthread_cond_signal
deactivate sub
deactivate main
deactivate sub

@enduml