optimistic_yield is a yield, not a delay, and avoids yielding if last yield has occurred recently enough.

dok-net · dok-net · commit 6cfbee74576a · 2020-01-18T15:54:04.000+01:00
diff --git a/tests/host/common/Arduino.cpp b/tests/host/common/Arduino.cpp
@@ -44,7 +44,6 @@ extern "C" bool can_yield()
 
 extern "C" void optimistic_yield (uint32_t interval_us)
 {
-    usleep(interval_us);
 }
 
 extern "C" void esp_yield()

Original file line number	Diff line number	Diff line change
`@@ -44,7 +44,6 @@ extern "C" bool can_yield()`
`44`	`44`
`45`	`45`	`extern "C" void optimistic_yield (uint32_t interval_us)`
`46`	`46`	`{`
`47`		`- usleep(interval_us);`
`48`	`47`	`}`
`49`	`48`
`50`	`49`	`extern "C" void esp_yield()`