Combining channels and goroutines

Now that we know the fundamental tools and properties of Go concurrency, we can use them to build better tools for our applications. We will see some examples that make use of channels and goroutines to solve real-world problems.

Rate limiter

A typical scenario is having a web API that has a certain limit to the number of calls that can be done in a certain period of time. This type of API will just prevent the usage for a while if this threshold is crossed, making it unusable for the time being. When creating a client for the API, we need to be aware of this and make sure our application does not overuse it.

That's a very good scenario where we can use time.Ticker to define...