title: Is lua table thread safe?
body: <p>Say, I have a lua table <code>t={"a"={}, "b"={}}</code>.</p>
  
  <p>My question is, I have two threads, thread A, thread B.
  And if I create two lua_State individually for these two threads through lua_newthread, and thread A only read/write <code>t.a</code>, thread B only read/write <code>t.b</code>.</p>
  
  <p>Should I use lua_lock in each thread above?</p>
  
  <p>If the answer is YES, then, does any of operation on <code>t</code> need a lua_lock?</p>