Serialize only synapses that exist

[stiber]

What kind of issue is this?

• [ ] Bug report
• [ ] Feature request
• [ ] Question not answered in documentation
• [X] Cleanup needed

Currently, we serialize the entirety of synapse data structures. It would be better to only serialize the segments of those structures that correspond to synapses that exist. The problem could be that this isn't a single block of contiguous memory, so we would have to add some additional complexity to the code that marshals/unmarshals data to prepare for serialization or postprocess as part of deserialization.

What is affected by this?

How do we replicate the issue/how would it work?

Expected behavior (i.e. solution or outline of what it would look like)

Other Comments

[stiber]

Have we concluded that this is better handled at deserialization time?

[stiber]

Actually, it seems like this is not worth it; it only saves some file space, at the cost of significant code complexity.