Add nop logger

Author: frozenbonito

Diff for: errors.go

@@ -44,6 +44,12 @@ type Logger interface {
 	Print(v ...interface{})
 }
 
+// NopLogger is a nop implementation of the Logger interface.
+type NopLogger struct{}
+
+// Print implements Logger interface.
+func (nl *NopLogger) Print(_ ...interface{}) {}
+
 // SetLogger is used to set the default logger for critical errors.
 // The initial logger is os.Stderr.
 func SetLogger(logger Logger) error {