setManualExposure abstract method
Manual exposure: fixes ISO (iso, e.g. 100..3200) and shutter time
(exposureNanos, in nanoseconds, e.g. 1/50s = 20_000_000). Both are
clamped to the device's supported range. Pass iso <= 0 to restore
automatic exposure (and re-enable exposure-compensation bias).
Implementation
void setManualExposure(int textureId, double iso, double exposureNanos);