code: @Override
      public void setRequestHeader(Header header) {
          
          Header[] headers = getRequestHeaderGroup().getHeaders(header.getName());
          
          for (int i = 0; i < headers.length; i++) {
              getRequestHeaderGroup().removeHeader(headers[i]);
          }
          
          getRequestHeaderGroup().addHeader(header);
          
      }
docs: Sets the specified request header, overwriting any previous value.
  Note that header-name matching is case insensitive.
  
  @param header the header