Test IMDClient `timeout` kwarg, add helpful hint to use it

[ljwoods2]

Is your feature request related to a problem?

Timeout defaults to 5 seconds but isn't tested. This can lead to confusing cases where the stream ends during infrequent transmission despite the simulation continuing.

Describe the solution you'd like

Test that the kwarg performs as expected with a parameterized test.

• Change default value to 600 seconds

• warn if user passes in an overly optimistic timeout, like <=1 second

• find some way to notify user if a timeout error was the reason the client stopped (warning? wrapping TImeoutError in EOFError?)

  imdclient/imdclient/IMDClient.py

  Line 514 in 07069e1

  def _read(self, buf):

[orbeckst]

We definitely need to change the default (conclusion from meeting today where @HeydenLabASU reported mysterious failures of a 500k system on the first frame). @amruthesht is putting up a PR based on his branch https://github.com/Becksteinlab/imdclient/tree/socket-timeout

[ljwoods2]

600 seconds seems like a long time, could we issue a warning based on some combination of IMD output frequency and n_atoms and give a reasonable suggestion?

[HeydenLabASU]

we'd have to work out what these combinations look like exactly. Is there any harm in having a longer timeout? If not, I'd prefer erring on the side of higher stability