fix a bug of socket.write function

[itgou]

hello, when call write func with default encode utf8 and callback , I think it is more convenience to only pass to params: (buffer,cb); Nodejs also did it this way.

[Rapsssito]

@itgou, thanks for the PR! However, while this is correct as implementation, it must also be reflected in the type declaration file for the Typescript users. If you do not have knowledge about JSDoc, I can take your implementation and add the corresponding JSDoc.