wbr><span class="type-parameter"><a href="https://api.flutter.dev/flutter/dart-ui/Color-class.html">Color</a>?</span>, <span class="type-parameter">S</span>&gt;</span>?</span> <span class="parameter-name">stateEvaluator</span>, </span><span class="parameter" id="-param-keyEvaluator"><span class="type-annotation"><a href="../state_machine_animation/KeyEvaluatorFunction.html">KeyEvaluatorFunction</a><span class="signature">&lt;<wbr><span class="type-parameter"><a href="https://api.flutter.dev/flutter/dart-ui/