title: Sharing a Read-only Reference Between Threads
body: <p>assume we have 2 threads, thread A and thread B.</p>
  
  <p>thread A is the main method and contain large data structures. </p>
  
  <p>is it possible to create a second thread and pass the address(a pointer) of the data structure (local to thread A) to thread B so both thread can read from the data structure? </p>
  
  <p>the point of this is to avoid the need to duplicate the entire data structure on thread B or spend a lot of time pulling relevant information from the data structure for thread B to use</p>
  
  <p>keep in mind that neither thread is modifying the data</p>