* Sorry. One more question.
The ws2812 has only one DIN and can be controlled by serial communication using only one port(and they can be daisy-chained by its internal shift register).
It seemed to me that this crate is using only MOSI out of SCLK/MOSI/MISO/CS to control the LEDs via SPI communication, does this mean that it is consuming SPI so that it can  communicate at the exact timing?
I suppose I could use cortex\_m::Delay, for example, to control timing with a single GPIO, but is that not a good idea?
Is it common to use only SPI MOSI for serial communication like this?