code: func (r *GoHeader) Get(key string) (value []string) {
  	if !r.isResponse {
  		value = r.Source.(*GoRequest).Original.Header[key]
  		if len(value) == 0 {
  			if ihead := r.Source.(*GoRequest).Original.Header.Get(key); ihead != "" {
  				value = append(value, ihead)
  			}
  		}
  	} else {
  		value = r.Source.(*GoResponse).Original.Header()[key]
  	}
  	return
  }
docs: // Gets the header key