ASAN_ONLY(to->asan_ctx_ = from);
ASAN_START_SWITCH(from->asan_stop_ ? nullptr : &fake_stack, to->asan_stack_, to->asan_stack_size_);
swapcontext(&from->uc_, &to->uc_);
ASAN_ONLY(to->asan_ctx_ = from);
ASAN_START_SWITCH(from->asan_stop_ ? nullptr : &fake_stack, to->asan_stack_, to->asan_stack_size_);
swapcontext(&from->uc_, &to->uc_);