Consider separating client construction and cluster connection

[yuce]

Currently HazelcastClient tries to connect to the Hazelcast cluster during construction. This is unexpected and probably something we shouldn't do in the constructor.

It would be better to separate client instance construction and cluster connection steps. Something along the lines of

hz = HazelcastClient()
hz.connect()

That also gives us the opportunity to assign listeners, etc. after creating the client instance:

hz = HazelcastClient()
hz.add_lifecycle_listener( ... )
# ...
hz.connect()

[Kilo59]

I like it.

I think adding a connect=True/False keyword argument could also be a good idea.

This is how pymongo behaves. Although they default to connect=True. https://pymongo.readthedocs.io/en/stable/api/pymongo/mongo_client.html#pymongo.mongo_client.MongoClient

MongoClient(host='localhost', port=27017, document_class=dict, tz_aware=False, connect=True, **kwargs)