thread '<main>' panicked at 'assertion failed: self.units.get(&unit_info.unit_id).is_none()', core/src/internal_state.rs:228
stack backtrace:
   1:     0x563605358c8f - std::sys::backtrace::tracing::imp::write::h3800f45f421043b8
   2:     0x56360535ba9b - std::panicking::default_hook::_$u7b$$u7b$closure$u7d$$u7d$::h0ef6c8db532f55dc
   3:     0x56360535b723 - std::panicking::default_hook::hf3839060ccbb8764
   4:     0x56360535264d - std::panicking::rust_panic_with_hook::h5dd7da6bb3d06020
   5:     0x56360529507f - std::panicking::begin_panic::h4c14e704ed94392f
   6:     0x5636052af5ec - core::internal_state::InternalState::add_unit::hc74b1e8713abe737
   7:     0x5636052a159c - core::Core::do_core_event::h637259803bbd4608
   8:     0x5636052a66d8 - core::Core::simulation_step::haeaacd8406f42bf0
   9:     0x5636052a88a2 - core::Core::do_command::had50e6564e64caaa
  10:     0x56360526e730 - zoc::tactical_screen::TacticalScreen::handle_event_lmb_release::h8aa06200b221289d
  11:     0x5636052793f5 - _<tactical_screen..TacticalScreen as screen..Screen>::handle_event::hd894107c308b2557
  12:     0x5636052349f2 - zoc::main::h308ba5ec18216eed
  13:     0x56360535b368 - std::panicking::try::call::hbbf4746cba890ca7
  14:     0x56360536540b - __rust_try
  15:     0x5636053653ae - __rust_maybe_catch_panic
  16:     0x56360535ae0e - std::rt::lang_start::hbcefdc316c2fbd45
  17:     0x7f49e8bb12b0 - __libc_start_main
  18:     0x563605233899 - _start
  19:                0x0 - <unknown>