# SimplePodDefinitionRegistry constructor

SimplePodDefinitionRegistry()

A basic registry for managing pod definitions.

This registry stores and retrieves PodDefinitions by name.
It provides the ability to:

- Register new pod definitions.
- Look up existing pod definitions.
- Check if a pod definition exists.
- Remove pod definitions.
- Track the total count and names of registered definitions.
- Handle conflicts with alias names inherited from SimpleAliasRegistry.

This is commonly used as the backbone for dependency injection containers, where pods must be defined before they can be instantiated.

### Example usage:

    void main() {
      final registry = SimplePodDefinitionRegistry();

      // Create a simple pod definition (hypothetical).
      final userPod = PodDefinition('UserPod');

      // Register it.
      registry.registerDefinition('user', userPod);

      // Retrieve it.
      final retrieved = registry.getDefinition('user');
      print(retrieved?.name); // Output: UserPod

      // Check existence.
      print(registry.containsDefinition('user')); // true

      // Get total count.
      print(registry.getDefinitionCount()); // 1

      // Remove definition.
      registry.removeDefinition('user');

      // Accessing a removed pod throws an exception.
      try {
        registry.getDefinition('user');
      } catch (e) {
        print(e); // NoSuchPodDefinitionException: No pod named 'user' is defined
      }
    }

Creates a new simple pod definition registry instance.

Example:

    final registry = SimplePodDefinitionRegistry();

## Implementation

    SimplePodDefinitionRegistry();