This is the v1 version, had the v2 before.

logger.go

@@ -0,0 +1,8 @@
+package imap
+
+// Logger is the behaviour used by server/client to
+// report errors for accepting connections and unexpected behavior from handlers.
+type Logger interface {
+	Printf(format string, v ...interface{})
+	Println(v ...interface{})
+}