improve interop with other libs/stdlib

logging/errs.go

@@ -1,7 +1,7 @@
 package logging
 
 import (
-	`errors`
+	"errors"
 )
 
 var (
@@ -12,6 +12,8 @@ var (
 		exists with too restrictive perms to write/append to, and/or could not be created.
 	*/
 	ErrInvalidFile error = errors.New("a FileLogger was requested but the file does not exist and cannot be created")
+	// ErrInvalidRune is returned if a rune was expected but it is not a valid UTF-8 codepoint.
+	ErrInvalidRune error = errors.New("specified rune is not valid UTF-8 codepoint")
 	// ErrNoEntry indicates that the user attempted to MultiLogger.RemoveLogger a Logger but one by that identifier does not exist.
 	ErrNoEntry error = errors.New("the Logger specified to be removed does not exist")
 )