Change prefetch on regions to 3 to prevent stutter during sync

core/core.go

@@ -38,7 +38,7 @@ const (
 	c_regionRetryThreshold                     = 1200    // Number of times a block is retry to be appended before eviction from append queue in Region
 	c_zoneRetryThreshold                       = 600     // Number of times a block is retry to be appended before eviction from append queue in Zone
 	c_maxFutureBlocksPrime              uint64 = 3       // Number of blocks ahead of the current block to be put in the hashNumberList
-	c_maxFutureBlocksRegion             uint64 = 2
+	c_maxFutureBlocksRegion             uint64 = 3
 	c_maxFutureBlocksZone               uint64 = 30
 	c_appendQueueRetryPriorityThreshold        = 5  // If retry counter for a block is less than this number,  then its put in the special list that is tried first to be appended
 	c_appendQueueRemoveThreshold               = 10 // Number of blocks behind the block should be from the current header to be eligble for removal from the append queue