State immunity — Jurisdictional immunity — Action against foreign State instrumentality — Commercial activity — Activities taken in connection with commercial activity performed outside jurisdiction — Default judgment entered for failure to make payments under loan agreements — payments to be made in United States — Whether reliance by plaintiff upon agents in United States to collect sums due to it constitutes direct effect in United States sufficient to establish jurisdiction — Whether “good cause” shown for denying motion for default judgment — The law of the United States