Moved to the newly created "Experimental Firmwares" category.
I'm very interested in an RTOS for Flutter. I've used SEGGER Embos before and it was very nice.
I've thought about how a simple RTOS designed for Arduino users might work, where there are simply more than one "Loop" routines. I think making an RTOS simpler and accessible to casual Arduino users would give those users access to a lot more power.
We will also have people developing a bare metal GCC version of Flutter that should be good for integrating into any RTOS. I would also love to see which ones people recommend!