我安装了 webdev 来运行 dart web，但是当我想运行 webdev 时，它显示错误：
Building package executable...
Failed to build webdev:webdev:
../../.pub-cache/hosted/pub.dartlang.org/dds-2.1.6/lib/src/cpu_samples_manager.dart:54:21: Error: Type 'CpuSamplesEvent' not found.
void cacheSamples(CpuSamplesEvent samples) {
^^^^^^^^^^^^^^^
../../.pub-cache/hosted/pub.dartlang.org/dds-2.1.6/lib/src/cpu_samples_manager.dart:54:21: Error: 'CpuSamplesEvent' isn't a type.
void cacheSamples(CpuSamplesEvent samples) {
^^^^^^^^^^^^^^^
我该如何修复它？