asDiffieHellmanTr31KeyBlockOrNull
Casts this IncomingKeyMaterial as a DiffieHellmanTr31KeyBlock and retrieves its aws.sdk.kotlin.services.paymentcryptographydata.model.IncomingDiffieHellmanTr31KeyBlock value. Returns null if the IncomingKeyMaterial is not a DiffieHellmanTr31KeyBlock.