NTCP: Reduce max writer threads

router/java/src/net/i2p/router/transport/ntcp/NTCPTransport.java

@@ -825,7 +825,7 @@ public class NTCPTransport extends TransportImpl {
     private static final int MIN_CONCURRENT_READERS = 2;  // unless < 32MB
     private static final int MIN_CONCURRENT_WRITERS = 2;  // unless < 32MB
     private static final int MAX_CONCURRENT_READERS = 4;
-    private static final int MAX_CONCURRENT_WRITERS = 4;
+    private static final int MAX_CONCURRENT_WRITERS = 3;
 
     /**
      *  Called by TransportManager.