The source of most issues with concurrency is figuring out how to share information safely, and provide access to that information, between multiple threads. The simplest solution would seem to be to have an object that both threads can have access to, and modify, in order to communicate with the other thread. This seemingly innocent strategy is easier suggested than done. Let's look at this example, where two threads are sharing the same stack of web pages to scrape. They will need to know which web pages have been completed, and which web pages the other thread is currently working on.
We will use a simple map for this example, as shown in the following code:
siteStatus := map[string]string{
"http://example.com/page1.html" : "READY",
"http://example.com/page2.html" : "READY",
"http://example.com/page3...
