fix(pbuf): wrong pointer

pbuf/pooler.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"io"
 	"reflect"
+	"unsafe"
 )
 
 // UserBuffer with customizable user data structure inside.
@@ -18,6 +19,7 @@ func (bufpooler[USRDAT]) New(config any, pooled UserBuffer[USRDAT]) UserBuffer[U
 	switch c := config.(type) {
 	case int:
 		pooled.Grow(c)
+		*(*[]byte)(unsafe.Pointer(&pooled.Buffer)) = pooled.Bytes()[:c]
 		if c != pooled.Len() {
 			panic("unexpected bad buffer Grow")
 		}