Increase maximum packet fragments to make room for huge multicasts with certificates of membership tagged onto them. This likely will not actually increase the number of fragments in practice much, since these are then subsequently compressed. But the buffer needs to be allocated with room for them, otherwise these packets get dropped with a range_error exception internally.

node/Constants.hpp

@@ -158,7 +158,7 @@ error_no_byte_order_defined;
  * The actual spec allows 16, but this is the most we'll support right
  * now. Packets with more than this many fragments are dropped.
  */
-#define ZT_MAX_PACKET_FRAGMENTS 3
+#define ZT_MAX_PACKET_FRAGMENTS 4
 
 /**
  * Timeout for receipt of fragmented packets in ms