class WEBrick::HTTPProxyServer

def choose_header(src, dst)
  connections = split_field(src['connection'])
  src.each{|key, value|
    key = key.downcase
    if HopByHop.member?(key)          || # RFC2616: 13.5.1
       connections.member?(key)       || # RFC2616: 14.10
       ShouldNotTransfer.member?(key)    # pragmatics
      @logger.debug("choose_header: '#{key}: #{value}'")
      next
    end
    dst[key] = value
  }
end