sync.WaitGroup
- Go by Example: WaitGroups
To wait for multiple Goroutine to finish, we can use a wait group.
A WaitGroup must not be copied after first use.
Share memory by communicating, don’t communicate by sharing memory
sync.Cond
Cond implements a conditional variable that can be used in scenarios where multiple Readers are waiting for a shared resource ready (if there is only one read and one write, a lock or Go Channel takes care of it).