State immunity — Jurisdictional immunity — Commercial activity exception — Foreign government agency — Claim based upon commercial activity carried on in the United States — Whether including claim for damage suffered abroad — Decision turning on whether act causing damage constituting integral part of commercial activity carried on in the United States — Requirement to look at transaction as a whole — Shipment to Egypt of wheat purchased by Egyptian government agency in the United States — Action against government agency for delaying unloading of vessel in Egypt — Whether action based upon commercial activity carried on in the United States — Counterclaim exception — Whether including crossclaims — Relationship between counterclaim and commercial activity exceptions — Whether finding by court that counterclaim exception inapplicable barring application of commercial activity exception — United States Foreign Sovereign Immunities Act 1976 — The law of the United States