When we’re spinning off many goroutines to do their thing, we want to keep track of them so that the main goroutine doesn’t just finish up and exit before everyone else is done. That’s where the WaitGroup comes in. Each time one of our goroutines wraps up its task, it lets the WaitGroup know.
Map is a built-in type that acts as a key-value storage. Unlike arrays where you’re stuck with keys as increasing indices like 0, 1, 2, and so on, with maps, the key can be any comparable type.
Mutex in Go has two main flows: Lock and Unlock and 2 modes: Normal and Starvation Mode. The state field of mutex is a 32-bit integer that represents the current state, it’s divided into multiple bits that encode various pieces of information about the mutex.
As always, we’ll start with the basics and then dig a bit deeper. Don’t worry, Go arrays get pretty interesting when you look at them from different angles. Arrays in Go are a lot like those in other programming languages. They’ve got a fixed size and store elements of the same type in contiguous memory locations.
The defer statement actually has 3 types: open-coded defer, heap-allocated defer, and stack-allocated. Each one has different performance and different scenarios where they’re best used, which is good to know if you want to optimize performance.
Vendoring is a different strategy as it keeps a copy of all your project’s dependencies directly within the project’s directory, rather than relying on an external cache.