code: func (h *ResponseHeader) CopyTo(dst *ResponseHeader) {
  	dst.Reset()
  
  	dst.disableNormalizing = h.disableNormalizing
  	dst.noHTTP11 = h.noHTTP11
  	dst.connectionClose = h.connectionClose
  	dst.noDefaultContentType = h.noDefaultContentType
  
  	dst.statusCode = h.statusCode
  	dst.contentLength = h.contentLength
  	dst.contentLengthBytes = append(dst.contentLengthBytes[:0], h.contentLengthBytes...)
  	dst.contentType = append(dst.contentType[:0], h.contentType...)
  	dst.server = append(dst.server[:0], h.server...)
  	dst.h = copyArgs(dst.h, h.h)
  	dst.cookies = copyArgs(dst.cookies, h.cookies)
  }
docs: // CopyTo copies all the headers to dst.