This is perhaps one of the few places where software developers could learn something from hardware development: In hardware description languages everything happens in parallel by default. A large chip project has many components that communicate typically fully asynchronously over some network / bus. Tools for debugging these systems are

- A GUI that allows one to trace all state changes down to the single bit level.

- Assertions based on linear temporal logic to verify invariants.

- Conventions around how to model transactions at various levels of abstraction, as well on how to monitor and extract these transaction from the "wire protocol".