+In Go 1.6, the runtime +added lightweight, +best-effort detection of concurrent misuse of maps. This release +improves that detector with support for detecting programs that +concurrently write to and iterate over a map. +
++As always, if one goroutine is writing to a map, no other goroutine should be +reading (which includes iterating) or writing the map concurrently. +If the runtime detects this condition, it prints a diagnosis and crashes the program. +The best way to find out more about the problem is to run the program +under the +race detector, +which will more reliably identify the race +and give more detail. +
+