Module shutdown

Shutdown related code.

A global flag indicates when the application is shutting down so actions can be taken at different parts of the codebase.

Statics

• IS_SHUTTING_DOWN
  A flag to indicate if Zebra is shutting down.

Functions

• is_shutting_down
  Returns true if the application is shutting down.
• set_shutting_down
  Sets the Zebra shutdown flag to true.