Slightly reduces memory overhead by replacing superfluous property with getter/setter.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

AFAIK getters/setters like this incur noticeable overhead, so perhaps we should be adjusting the documentation to more strongly recommend socket over connection.

Also if we're making this change we should also replace all usage of .connection in core with .socket to avoid the overhead.