beginPtyHold method
void
beginPtyHold()
Suppress PTY SIGWINCH while host chrome animates (e.g. sidebar). Engine and mirror still track the live layout; call endPtyHold to flush one SIGWINCH. Use a GlobalKey<TerminalViewState> to reach these from the host.
Implementation
void beginPtyHold() => _viewportController.beginPtyHold();