Authenticating subject with shiro in spring application that uses atmosphere for sockets

I have a Spring-boot web application that uses Apache Shiro for security management. The web application also uses the Atmosphere framework for socket communication.

Whilst working with it I have a requirement to authenticate a user who is currently logged in when I receive /socket request to atmosphere. However, when trying to access the Shiro Subject I get the following error:

No SecurityManager accessible to the calling code, either bound to the org.apache.shiro.util.ThreadContext or as a vm static singleton.  This is an invalid application configuration.

I also have a filter added to my SecurityManager for /socket. Regardless, I continue to get the above error when I try to authenticate the user with atmosphere for socket connections.

I have searched up quite a lot on the web and haven't found an answer that explains what's happening thoroughly. I found many posts that mentioned something about the thread pool used by atmosphere is different from that which is allocated to servlet requests. Thus, async requests that reach atmosphere have no context of the original user. I also read a workaround here, which is quite old. I tried some of the things mentioned in the comments too.

Note: I am a newbie to the Spring, Shiro and Atmosphere frameworks. I understand things in a more systems-level perspective.

I would highly appreciate if I can get some explanation (or some link that might help) as to what is happening with each of these things and why it is producing the error above. Most of the online material I have read regarding this seems to be very vague and does not cover as an exclusive answer.

If I am not mistaken when the Spring application launches it also loads the Shiro and Atmosphere, related classes. The requests arrive at the Apache server and are delegated to a class based on annotations. Spring/Apache stores per request info (some cookie or session token) and subsequent requests are mapped according to this. However, the information stored between requests that hit the Atmosphere related (ex: onRequest) endpoints and the rest are not shared, hence I cannot use the same subject info.

I have sincerely searched a lot trying to understand and would like an elaborate explanation. I hope this question is not regarded unsuitable to the forum.

Thank you Shabir