Using emit and events for event logging

Events in Solidity are used to log information. Off-chain client applications can subscribe and listen for any events that are being emitted in the blockchain. These client applications use the Remote Procedure Call (RPC) interface to interact with the Ethereum nodes and are notified upon event emission. 

By using the Solidity language, your contracts can emit events, but they cannot listen to or read the data of a triggered event. Events are always inherited from contracts, which means that you can emit events that are defined in your contract inheritance tree.

When you emit an event, its arguments are stored in the transaction log. These logs are related to the contract address and are stored in the blockchain's block. These events will be available forever since they are present in the block. However, this might change...