isActive abstract method

Returns whether this application context is currently active.

An active context has been successfully refreshed and is fully operational. This is the normal running state of a context between refresh and close.

State Transitions:

• false → true: When refresh() completes successfully
• true → false: When close() is called
• Irreversible: Once false, cannot become true again

Usage:

if (context.isActive()) {
  // Safe to use context and retrieve pods
  final service = context.getPod<MyService>();
  service.doSomething();
} else {
  throw StateError('Context is not active');
}