it favors production when the witness testifies."); United States v. Giampa, No. S 92 CR. 437 (PKL), 1992 WL 296440, at •4 (S.D.N.Y. Oct. 7, 1992) (Leisure, J.) (modifying subpoenas for impeachment materials "to make them returnable at the time when [the witness] testifies at trial"). To avoid delay in tri