In a thread which never calls asio::io_conterxt.run(), must I invoke post() to dispatch tasks to the thread which has called io_context.run()?

In a thread which has not ever called and would never call asio::io_context.run(), must I invoke post() or dispatch() to dispatch tasks to the thread which has called asio::io_context.run()?

Is it safe to directly call asio::async_write() or asio::async_read() in a thread which has not ever called and would never call asio::io_context.run() to dispatch tasks to the thread which has called asio::io_context.run()?