class HTTP::Timeout::PerOperation

def readpartial(size, buffer = nil)
  timeout = false
  loop do
    result = @socket.read_nonblock(size, buffer, :exception => false)
    return :eof   if result.nil?
    return result if result != :wait_readable
    raise TimeoutError, "Read timed out after #{@read_timeout} seconds" if timeout
    # marking the socket for timeout. Why is this not being raised immediately?
    # it seems there is some race-condition on the network level between calling
    # #read_nonblock and #wait_readable, in which #read_nonblock signalizes waiting
    # for reads, and when waiting for x seconds, it returns nil suddenly without completing
    # the x seconds. In a normal case this would be a timeout on wait/read, but it can
    # also mean that the socket has been closed by the server. Therefore we "mark" the
    # socket for timeout and try to read more bytes. If it returns :eof, it's all good, no
    # timeout. Else, the first timeout was a proper timeout.
    # This hack has to be done because io/wait#wait_readable doesn't provide a value for when
    # the socket is closed by the server, and HTTP::Parser doesn't provide the limit for the chunks.
    timeout = true unless @socket.to_io.wait_readable(@read_timeout)
  end
end