Fixed a problem that connection from Socket.IO Client v2 failed.

[penguinlab]

Fixes #1017

Fixed a problem that connection from Socket.IO Client v2 failed.

The cause is an error in the skip range of the index of the frame. It appears to have been introduced during the change between versions 2.0.9 and 2.0.11.

If there is no problem, please merge.

[mrniko]

Does it work with v4?

[penguinlab]

Does it work with v4?

Yes. I tried connecting from the Socket.IO Client v2,v3,v4 and confirmed that it works.
Also, I confirmed that the processing of the data field of packets is not affected.

[mylostway]

已收到你发来的邮件，我会尽快回复

[penguinlab]

@mrniko
The cause of the bug is explained in more detail below.

The value of the namespace field of the CONNECT packet varies depending on the version of the Socket.IO Client. Specifically, QueryString is included in the value of the namespace field only when connecting from Socket.IO Client v2.

Due to this difference, the bug is only noticeable when connecting from Socket.IO Client v2.

The following is the Connection packet when connecting from Socket.IO Client v2, v3, v4.

Connect with Socket.IO Client v2 (socket.io-client: 2.5.0)

The value of namespace field contains a QueryString.

Connect with Socket.IO Client v3 (socket.io-client: 3.1.3)

The value of namespace field does not contain a QueryString.

Connect with Socket.IO Client v4 (socket.io-client: 4.8.1)

The value of namespace field does not contain a QueryString.

[mrniko]

Thanks for the explanation and your work! Merged