enableKeepAlive

when true (the default), Terminal polls the terminal in the background once keepAliveInterval has passed without any other call, so a terminal that goes unreachable while idle is still noticed (moving Terminal.getState to TerminalState.DISCONNECTED) instead of only surfacing on the next real call. Any call made in the meantime resets the idle timer, so this is a no-op while transactions are already flowing frequently enough on their own.