default_context.go
func (d *DefaultContext) LogField(key string, value interface{}) {
	d.logger = d.logger.WithField(key, value)
}
func (d *DefaultContext) LogField(key string, value interface{}) {
	d.logger = d.logger.WithField(key, value)
}
func ( d * DefaultContext ) LogField ( key string , value interface { } ) { d . logger = d . logger . WithField ( key , value ) }
// LogField adds the key/value pair onto the Logger to be printed out
// as part of the request logging. This allows you to easily add things
// like metrics (think DB times) to your request.
LogField adds the key / value pair onto the Logger to be printed out as part of the request logging . This allows you to easily add things like metrics ( think DB times ) to your request .