message: Remove unnecessary using
diff: import { WarningMessageObserver } from '../../../src/observers/WarningMessageObserver';
  import { assert, use as chaiUse, expect, should } from 'chai';
  import { getFakeVsCode, getMSBuildDiagnosticsMessage, getOmnisharpMSBuildProjectDiagnosticsEvent, getOmnisharpServerOnErrorEvent } from '../testAssets/Fakes';
  -import { BaseEvent } from '../../../src/omnisharp/loggingEvents';
  import { vscode } from '../../../src/vscodeAdapter';
  import { TestScheduler } from 'rxjs/testing/TestScheduler';
  import { Observable } from 'rxjs/Observable';
  