Function command 

pub(super) fn command(
    ssh_path: &Path,
    dest: &SshDest,
    (cmd, cmd_args, cwd): (&str, &[String], &str),
    askpass_secret: Option<&str>,
    auth_key: &str,
    block_id: &str,
) -> CommandBuilder

Pane block_id’s ssh (ssh_path) to dest, running cmd (cmd_args) in cwd there, sharing the channel’s connection to it. askpass_secret: an agent’s SSH shell, whose every ssh prompt goes to the user through the askpass bridge, never into this terminal, which the agent reads.