Using atomic operations and mutex

In a language like Go, where you have build in asynchronous operations and parallelism, it becomes important to consider things such as thread safety. For example, it is dangerous to access a map from multiple goroutines simultaneously. Go provides a number of helpers in the sync and sync/atomic packages to make sure that certain events occur only once or that goroutines can serialize on an operation.
This recipe will demonstrate the use of these packages to safely modify a map with various goroutines and to keep a global ordinal value that can be safely accessed by numerous goroutines. It will also showcase the Once.Do method, which can be used to ensure that something is only done by a Go application once, such as reading a config or initializing a variable.

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