What is the test for federal habeas corpus relief for a state prisoner before trial?

"Although federal habeas corpus relief is not ordinarily available to a state prisoner before trial, the peculiar nature of the right to a speedy trial requires an exception to this rule. The detrimental consequences of delay have been repeatedly catalogued. citations omitted Denial of a speedy trial adversely affects both the prisoner's present circumstances and his ability to defend himself in the future. Only a present remedy can lift its dual oppressions."

Kane v. Virginia, 419 F.2d 1369, 1372 (4th Cir.1970).