What is "Sim blocking" (seen in tomcat doc)?

Question

I saw the following description in the official tomcat configuration documentation (APR connector description omitted):

             Java Blocking Connector       Java Nio Blocking Connector
Classname         Http11Protocol                  Http11NioProtocol   
Tomcat Version   3.x 4.x 5.x 6.x                       6.x            
Support Polling         NO                             YES            
Polling Size           N/A                   Unlimited - Restricted by mem
Read HTTP Request     Blocking                     Non Blocking
Read HTTP Body        Blocking                     Sim Blocking
Write HTTP Response   Blocking                     Sim Blocking
SSL Support           Java SSL                     Java SSL
SSL Handshake         Blocking                     Non blocking
Max Connections       maxThreads                   See polling size

What does "Sim Blocking" mean?

Answer 1

According to Filip Hanik, a Tomcat committer, it means "simulated blocking". (Reference: Tomcat User Mailing list post)

Answer 2

Just a guess, but it could stand for simulated blocking, meaning a blocking api wrapped around the underlying non-blocking nio api.