the privilege issue is not “controlling,” or where an immediate appeal will not materially advance the end of the case, the frank discussions that privileges are meant to protect will be chilled if the opportunity for immediate correction by an appellate court is not available. As for seeking a writ of mandamus as a substitute for an immediate appeal, mandamus is generally not available in Pennsylvania law as a vehicle for obtaining appellate review. The Superior and Commonwealth Courts may issue writs of mandamus to lower courts only regarding matters ancillary to appeals already pending within those courts’ respective jurisdictions. See 42 Pa.C.S. § 741; 42 Pa.C.S. § 761(c). See also Mun. Publications, Inc. v. Ct. of Com. Pl. of Phila. Cty., 507 Pa. 194, 489 A.2d 1286, 1288 (1985) (<HOLDING>); Bell Appeal, 396 Pa. 592, 152 A.2d 731 (1959)
holding that this court has authority in appropriate circumstances to issue writs under all writs act 28 usc  1651a holding that where an adversary proceeding continues the order  is no more a final decision than an order denying summary judgment or denying a request for additional discovery the litigation proceeds and the issue will be reviewed if it turns out to make a difference to an order that is independently appealable holding that district court had jurisdiction to consider claims under the all writs act holding that district courts have power to issue writs of prohibition to administrative agencies to prevent them from exceeding their jurisdiction holding that the superior court may not issue writs of prohibition to review an order denying recusal before final judgment