dispose method

void dispose()

Implementation

void dispose() {
  if (_disposed) return;
  _disposed = true;
  for (final surface in _surfaces.values) {
    for (final execution in surface.executions) {
      execution.cancelled = true;
    }
  }
  _surfaces.clear();
  _seen.clear();
  _semantics?.dispose();
  _semantics = null;
}