Package syncmap provides a concurrent map implementation. This was the prototype for sync.Map which was added to the standard library's sync package in Go 1.9. https://golang.org/pkg/sync/#Map.
Map is a concurrent map with amortized-constant-time loads, stores, and deletes. It is safe for multiple goroutines to call a Map's methods concurrently.
The zero Map is valid and empty.
A Map must not be copied after first use.