Returns the read-only information about this node.
mongos node, if any.
The first node from the nearestGroup.
See the nearest read preference.
The node which is the current primary one.
Returns a NodeSet with channels created to
upTo given maximum,
per each member of the set.
(Since version 0.12-RC1) Use
createNeededChannels with the explicit
(Since version 0.12-RC0) Unused