Map with concurrent access
Multiple readers, no writers is okay: https://groups.google.com/d/msg/golang-nuts/HpLWnGTp-n8/hyUYmnWJqiQJ One writer, no readers is okay. (Maps wouldn’t be much good otherwise.) Otherwise, if there is at least one writer and at least one more either writer or reader, then all readers and writers must use synchronization to access the map. A mutex works fine for this.