Function UA_Server_createSigningRequest 

pub unsafe extern "C" fn UA_Server_createSigningRequest(
    server: *mut UA_Server,
    certificateGroupId: UA_NodeId,
    certificateTypeId: UA_NodeId,
    subjectName: *const UA_String,
    regenerateKey: *const UA_Boolean,
    nonce: *const UA_ByteString,
    csr: *mut UA_ByteString,
) -> UA_StatusCode