Magento 2 Events
Events are dispatched by Magento 2 modules whenever specific actions are triggered.
When an event dispatches, it passes data to the observer that is configured to watch that event.
You can dispatch Magento 2 Events using the Magento\Framework\Event\Manager class.
This class can be obtained through dependency injection by defining the dependency in the constructor method of the class.

Magento 2 Observers
Observers are the particular classes that control the general behavior, performance, or change in the business logic of the store.
They are executed whenever a specific event for which they were set to listen is triggered.
To create an observer in Magento 2, you must place your class file under the ModuleRoot/Observer directory.
The observer class file should use Magento\Framework\Event\Observer and Magento\Framework\Event\ObserverInterface class
and define the executive function.

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