Function indy_register_payment_method 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn indy_register_payment_method(
    command_handle: Handle,
    payment_method: CString,
    create_payment_address: Option<CreatePaymentAddressCB>,
    add_request_fees: Option<AddRequestFeesCB>,
    parse_response_with_fees: Option<ParseResponseWithFeesCB>,
    build_get_payment_sources_request: Option<BuildGetPaymentSourcesRequestCB>,
    parse_get_payment_sources_response: Option<ParseGetPaymentSourcesResponseCB>,
    build_payment_req: Option<BuildPaymentReqCB>,
    parse_payment_response: Option<ParsePaymentResponseCB>,
    build_mint_req: Option<BuildMintReqCB>,
    build_set_txn_fees_req: Option<BuildSetTxnFeesReqCB>,
    build_get_txn_fees_req: Option<BuildGetTxnFeesReqCB>,
    parse_get_txn_fees_response: Option<ParseGetTxnFeesResponseCB>,
    build_verify_payment_req: Option<BuildVerifyPaymentReqCB>,
    parse_verify_payment_response: Option<ParseVerifyPaymentResponseCB>,
    cb: Option<ResponseEmptyCB>,
) -> Error