<ThemeProvider>
  <Checkbox
    onChange={(evt, checked) => {
      console.log('checked', checked)
    }}
  />
</ThemeProvider>

<ThemeProvider>
  <Checkbox
    defaultChecked={true}
    onChange={(evt, checked) => {
      console.log('checked', checked)
    }}
  />
</ThemeProvider>

<ThemeProvider>
  <WithState defaultState={true}>
    {(state, setState) => (
      <Checkbox
        checked={state}
        onChange={(evt, checked, name) => setState(checked)}
      />
    )}
  </WithState>
</ThemeProvider>