rpc: support returning nil pointer big.Ints (null)

rpc/utils.go

@@ -22,7 +22,6 @@ import (
 	crand "crypto/rand"
 	"encoding/binary"
 	"encoding/hex"
-	"math/big"
 	"math/rand"
 	"reflect"
 	"strings"
@@ -105,20 +104,6 @@ func formatName(name string) string {
 	return string(ret)
 }
 
-var bigIntType = reflect.TypeOf((*big.Int)(nil)).Elem()
-
-// Indication if this type should be serialized in hex
-func isHexNum(t reflect.Type) bool {
-	if t == nil {
-		return false
-	}
-	for t.Kind() == reflect.Ptr {
-		t = t.Elem()
-	}
-
-	return t == bigIntType
-}
-
 // suitableCallbacks iterates over the methods of the given type. It will determine if a method satisfies the criteria
 // for a RPC callback or a subscription callback and adds it to the collection of callbacks or subscriptions. See server
 // documentation for a summary of these criteria.