GCC on Xtensa (ESP32) generates an indirect function call for
std::atomic<bool>::load() instead of inlining it. This adds unnecessary
call overhead on the scheduler hot path where the remove flag is checked
multiple times per loop iteration.
std::atomic<uint8_t>::load() inlines correctly on all platforms,
producing a simple load instruction with memory barrier. This eliminates
5 indirect calls and saves 30 bytes of flash on the scheduler hot path.
J. Nick Koston
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