How to properly stop a goroutine in Go? Problems with terminating background tasks

Hello everyone! I'm a beginner Go developer and I'm having trouble managing goroutines. I'm writing a small service that periodically checks the state of an external API and updates a local cache. To do this, I launch a background goroutine with an infinite loop and time.Sleep. The problem is that when the program terminates (for example, with Ctrl+C) or when I need to restart the goroutine, I can't stop it properly. If I just exit main, the goroutine either hangs or panics. I tried using a global flag `var running bool` and checking it in the loop, but it doesn't work instantly, and sometimes the goroutine gets blocked on I/O operations. Here's an example of my code: ```go package main import ( "fmt" "time" ) func worker() { for { fmt.Print