What is the District Court's duty and what standard is the Court to apply to a habeas proceeding presenting a substantial and meritorious IAC claim of trial counsel which relies on post-conviction counsel as the basis for excusing the procedural default?

Does the burden shift to the state to argue the underlying IAC at trial claim does not have some merit, before a district court can dismiss a habeas petition, after the initial showing is made a claim is relying on Martinez v. Ryan, 132 S.Ct. 1309 (2012) and post-conviction counsel to excuse a procedural default?

What is the District Court's duty and what standard is the Court to apply to a habeas proceeding presenting a substantial and meritorious IAC claim of trial counsel which relies on post-conviction counsel as the basis for excusing the procedural default?