// Forwarder must be implemented by a forwarder contract used by a *relayer.Relayer.
// These methods are wrappers around the methods auto-generated by abigen.
//
// See `impls/gsn_forwarder/i_forwarder_wrapped.go` or 
// `impls/minimal_forwarder/i_minimal_forwarder_wrapped.go`for examples.
type Forwarder interface {
	GetNonce(opts *bind.CallOpts, from ethcommon.Address) (*big.Int, error)

	Verify(
		opts *bind.CallOpts,
		req ForwardRequest,
		domainSeparator,
		requestTypeHash [32]byte,
		suffixData,
		signature []byte,
	) (bool, error)

	Execute(
		opts *bind.TransactOpts,
		req ForwardRequest,
		domainSeparator,
		requestTypeHash [32]byte,
		suffixData,
		signature []byte,
	) (*types.Transaction, error)
}

// ForwardRequest must be implemented by a request type used by a forwarder contract.
//
// See `impls/gsn_forwarder/request.go` or `impls/minimal_forwarder/request.go`
// for examples.
type ForwardRequest interface {
	// FromSubmitTransactionRequest set the type underlying the ForwardRequest
	// using a *SubmitTransactionRequest.
	//
	// Note: not all fields in the *SubmitTransactionRequest need be used depending
	// on the implementation.
	FromSubmitTransactionRequest(*SubmitTransactionRequest)

	// Pack uses ABI encoding to pack the underlying ForwardRequest, appending
	// optional `suffixData` to the end.
	//
	// See examples/gsn_forwarder/IForwarderForwardRequest.Pack() or
	// examples/minimal_forwarder/IMinimalForwarderForwardRequest.Pack()
	// for details.
	Pack(suffixData []byte) ([]byte, error)
}

func NewIForwarderForwardRequest() common.ForwardRequest {
	return &IForwarderForwardRequest{}
}

cfg := &relayer.Config{
	// fields omitted
	NewForwardRequestFunc: NewIForwarderForwardRequest,
}

_, _ = relayer.NewRelayer(cfg)

func (s *RelayerService) SubmitTransaction(
	_ *http.Request,
	req *common.SubmitTransactionRequest,
	resp *common.SubmitTransactionResponse,
) error