error on send pdu

hi
i get error on sending this pdu
```
var pdu = new smpp.PDU( Buffer.from('0000008f000000050000000000000263313030380001013938393336363830373337300000013430343031303036363630300040000000000000080052050003f3020206310645000a063406450627063106470020062a0644064106460020062b0628062a0020062f06310020063306cc0633062a0645002006f006f906f306f906f306f306f906f306f906f506f1' , 'hex'));
session.send(pdu)
```
node:buffer:559
throw new ERR_INVALID_ARG_TYPE(
^

TypeError [ERR_INVALID_ARG_TYPE]: The "list[0]" argument must be an instance of Buffer or Uint8Array. Received an instance of Array
at new NodeError (node:internal/errors:371:5)
at Object.concat (node:buffer:559:13)
at PDU.encode (D:\wamp64\www\product\SmppClient\node_modules\smpp\lib\defs.js:545:17)
at PDU._filter (D:\wamp64\www\product\SmppClient\node_modules\smpp\lib\pdu.js:144:41)
at PDU.toBuffer (D:\wamp64\www\product\SmppClient\node_modules\smpp\lib\pdu.js:177:7)
at Session.send (D:\wamp64\www\product\SmppClient\node_modules\smpp\lib\smpp.js:247:19)
at Session. (D:\wamp64\www\product\SmppClient\project-test\fake_server.js:37:11)
at Session.emit (node:events:390:28)
at Session._extractPDUs (D:\wamp64\www\product\SmppClient\node_modules\smpp\lib\smpp.js:206:8)
at Socket. (D:\wamp64\www\product\SmppClient\node_modules\smpp\lib\smpp.js:93:8) {
code: 'ERR_INVALID_ARG_TYPE'
```