Function try_auto_factor 

async fn try_auto_factor(
    client: &BusClient,
    factor_id: AuthFactorId,
    meta: &VaultMetadata,
    profile: &TrustProfileName,
    config_dir: &Path,
    salt: &[u8],
) -> Result<Option<bool>>

Try to submit a non-interactive factor (SSH agent). Returns Ok(Some(true)) if vault is unlocked, Ok(Some(false)) if partial, Ok(None) if factor was not attempted, or Err on hard failure.