D语言消息传递等待

import std.stdio; 
import std.concurrency; 
import core.thread; 
import std.conv; 

void workerFunc(Tid tid) { 
   Thread.sleep(dur!("msecs")( 500 ),); 
   tid.send("hello"); 
}

void main() { 
   spawn(&workerFunc,thisTid);  
   writeln("Waiting for a message");  
   bool received = false;

   while (!received) { 
      received = receiveTimeout(dur!("msecs")( 100 ), (string message) { 
         writeln("received: ", message); 
      });

      if (!received) { 
         writeln("... no message yet"); 
      }
   } 
}