> On 22 Mar 2020, at 09:41, Frank Millman <fr...@chagford.com> wrote:
>
> On 2020-03-22 11:00 AM, Barry Scott wrote:
>>> On 22 Mar 2020, at 07:56, Frank Millman <fr...@chagford.com> wrote:
>>>
>>> On 2020-03-21 8:04 PM, Barry Scott wrote:
>>>> I'd look at the network traffic with wireshark to see if there is anything
>>>> different between edge and the other browsers.
>>>
>>> You are leading me into deep waters here :-) I have never used Wireshark
>>> before. I have now downloaded it and am running it - it generates a *lot*
>>> of data, most of which I do not understand yet!
>> You can tell wireshark to only capture on one interface and to only capture
>> packets for port 80.
>> (Captureing HTTPS means you cannot decode the packets without going deeper I
>> recall)
>> Then you can tell wireshark to decode the captured data for http to drop a
>> lot of the lower level details.
>
> Thanks. I am more or less doing that. Interestingly the [RST,ACK] messages
> appear on the tcp packets, so if I filter on http I do not see them.
>
>>>
>>> One thing immediately stands out. When I run it with MS Edge and Python3.8,
>>> it shows a lot of lines highlighted in red, with the symbols [RST,ACK].
>>> They do not appear when running Chrome, and they do not appear when running
>>> Python3.7.
>> As Chris said that should not happen.
>
> As I replied to Chris, they appear in packets sent *from* Python *to* Edge.
>
>>>
>>> I have another data point. I tried putting an asyncio.sleep() after sending
>>> each file. A value of 0.01 made no difference, but a value of 0.1 makes the
>>> problem go away.
>> What is the async wait to wait for the transmit buffers to drain?
>
> Not sure what you are asking. I am just doing what it says in the docs -
>
> =================
>
> write(data)
> The method attempts to write the data to the underlying socket immediately.
> If that fails, the data is queued in an internal write buffer until it can be
> sent.
>
> The method should be used along with the drain() method:
>
> stream.write(data)
> await stream.drain()
>
> =================
>
> coroutine drain()
> Wait until it is appropriate to resume writing to the stream. Example:
>
> writer.write(data)
> await writer.drain()
> This is a flow control method that interacts with the underlying IO write
> buffer. When the size of the buffer reaches the high watermark, drain()
> blocks until the size of the buffer is drained down to the low watermark and
> writing can be resumed. When there is nothing to wait for, the drain()
> returns immediately.
>
> =================
That you called drain() is what I was asking. I'm a Twisted user and have not
used asyncio yet.
Barry
>
> Frank
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