Merges the Subject's current {@link hunt.shiro.subject.Subject#getPrincipals()} with whatever may be in
any available session. Only updates the Subject's session if the session does not match the current principals
state.
@param subject the Subject for which principals will potentially be merged into the Subject's session.
Merges the Subject's current {@link hunt.shiro.subject.Subject#getPrincipals()} with whatever may be in any available session. Only updates the Subject's session if the session does not match the current principals state.
@param subject the Subject for which principals will potentially be merged into the Subject's session.