Better sender io errors (download also...)

[petersilva]

Robbie asked for better error messages... yeah...

• wrap all interactions with transfer protocols in try/except so instead of gettting stack traces we get a succinct summary:

I ran the flow tests and they pass.

[github-actions]

Test Results

209 tests   200 ✅  16s ⏱️
  1 suites    8 💤
  1 files      1 ❌

For more details on these failures, see this check.

Results for commit 5dfd33f.

[reidsunderland]

We lost some useful information with this change. Now we only see which file failed to send, before we got a more generic error, but we saw the full path.

This is what we got before:

sarracenia/sarracenia/flow/__init__.py

Lines 2545 to 2547 in 6ad476d

	logger.error("Delivery failed %s" % msg['new_dir'] + '/' +
	msg['new_file'])
	logger.debug('Exception details: ', exc_info=True)

The new message doesn't include the path:

sarracenia/sarracenia/flow/__init__.py

Lines 2403 to 2404 in 6ad476d

	except Exception as ex:
	logger.error( f"could not send inflight=None {new_file}: {ex}" )