protected void applyRealmsToSecurityManager(Collection<Realm> realms, SecurityManager securityManager) {
        assertRealmSecurityManager(securityManager);
        ((RealmSecurityManager) securityManager).setRealms(realms);
    }
Creates a new instance.  See the {@link #getInstance()} JavaDoc for detailed explanation of how an INI
source will be resolved to use to build the instance.
core/src/main/java/org/apache/shiro/ini/IniSecurityManagerFactory.java