Flutter counterpart: packages/flutter/lib/src/services.
Only the hardware keyboard, haptic feedback, the mouse cursor, the mouse tracking
annotation, state restoration, the application switcher description, the system overlay
style, TextInput / TextInputConnection / TextInputClient / TextSelectionDelegate,
text layout metric statics, the clipboard, text input formatters, SelectionChangedCause,
autofill (AutofillHints / AutofillClient / AutofillScope), keyboard-inserted
content, spell check, live text, process text, UndoManager / UndoManagerClient,
SystemContextMenuController, and re-exports of the text-input value types are here. Platform channels, the raw
keyboard, and the rest of system chrome wait.