Parallel relationship establishment
Parallel relationship establishment

We try now to connect inter-node drops parallely instead of sequentially. For
big graphs with lots of connections this took quite a while: Chen reported that
for a graph with 66k drops (so probably in the other of a few thousands of
connections) this took around 5 minutes.

The problem with parallel drop binding is that we might probably exhaust the
thread pools of the daemons hosting the drops, so we have to take care of
identifying when this happens and try again when the resources are free. This
implementation relies on calling _pyroReconnect with 10 retries, which does
exactly that. Internally _pyroReconnect sleeps 2 seconds after each try, so the
thing will explode after 20 seconds at the most, or more likely succeed.

Signed-off-by: Rodrigo Tobar <bd955c861cbec2e41c0959cf13c7f573fa307e58@icrar.org>

steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge