Multiple NodeHandle instances vs shared NodeHandle

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Conceptually, when writing a C++ node wherein several classes are instantiated, each responsible for their own publications and subscriptions, one can either instantiate a NodeHandle within each different class, on instantiate a single NodeHandle at top-level/outside, and pass pointers to that NodeHandle to each class.

Performance-wise, is one approach advisable over the other, or are they equivalent? How "expensive" is instantiating a NodeHandle object?