Can you explain the principle of Event Sourcing and its main features?

Event Sourcing is an architectural pattern where all changes to the system's state are stored as a sequence of events, rather than as the current state. Instead of storing only the final state of an object, the system keeps all the events that led to that state.

Key features of Event Sourcing:

• Storing change history: Each change is recorded as a separate event.
• Reconstructing state: The current state can be restored by sequentially applying all events.
• Audit and debugging: A complete history of changes facilitates analysis and debugging.
• Support for CQRS: Often used together with Command Query Responsibility Segregation to separate read and write operations.

Example: instead of storing the account balance, the system stores events like "deposit 100", "withdraw 50", etc., and the balance is calculated by summing these events.