Throw IllegalStateException if DynamicChannelBuffer exceed the maximum

ChannelBuffer size of 2gb. See #258

buffer/src/main/java/io/netty/buffer/DynamicChannelBuffer.java

@@ -73,6 +73,15 @@ public class DynamicChannelBuffer extends AbstractChannelBuffer {
         int minNewCapacity = writerIndex() + minWritableBytes;
         while (newCapacity < minNewCapacity) {
             newCapacity <<= 1;
+            
+            
+            // Check if we exceeded the maximum size of 2gb if this is the case then 
+            // newCapacity == 0
+            //
+            // https://github.com/netty/netty/issues/258
+            if (newCapacity == 0) {
+                throw new IllegalStateException("Maximum size of 2gb exceeded");
+            }
         }
 
         ChannelBuffer newBuffer = factory().getBuffer(order(), newCapacity);