Currently we have a soup in cpp/ with impl files in lib/ which is generally annoying. I propose we blow this up, & do something like this:

cpp/
  -> connector_impl.cc,h
  -> service_context.cc
  -> service.cc
  standalone/
  test/
    -> service_test.cc,h
  types/
    -> bind_source_info*, identity*, interface_provider_spec*,
  util/
    -> connect.h
    -> binder_registry.cc,h
    -> interface_binder.h, callback_binder.cc,h
    -> service_context_ref.cc,h
    -> interface_provider.cc,h
    -> init_commandline.cc
    -> initialize_base_and_icu.cc
    -> service_runner.cc,h

Additionally I propose flattening connector.h & connector_impl.cc/h. There's no real reason to have a virtual interface for this, considering ServiceContext etc are concrete classes.