`const internalMessage = internal({
            value: amount,
            to: toAddress,
            body: memo,
            bounce
        });

        const transfer = await wallet.createTransfer({
            authType: AUTH_TYPE.external,
            seqno: nonce,
            messages: [internalMessage],
            sendMode: SendMode.PAY_GAS_SEPARATELY,
            timeout: Math.floor(Date.now() / 1e3) + timeout,
            signer: () => {
                return Promise.resolve(Buffer.from(''));
            }
        });

        console.log('estimate:', await this.tonClient.estimateExternalMessageFee(wallet.address, {
            body: transfer,
            ignoreSignature: true,
            initCode: null,
            initData: null,
        }));`