code: func (decoder *HTTPDecoder) Register(f DecoderFunc, contentTypes ...string) {
  	p := newDecodePool(f)
  
  	for _, contentType := range contentTypes {
  		mediaType, _, err := mime.ParseMediaType(contentType)
  		if err != nil {
  			mediaType = contentType
  		}
  		decoder.pools[mediaType] = p
  	}
  }
docs: // Register sets a specific decoder to be used for the specified content types. If a decoder is
  // already registered, it is overwritten.