add usage example for Result

pkg/scale/README.md

@@ -159,6 +159,55 @@ result := scale.NewResult(int32(0), int32(0)
 result.Set(scale.Ok, 10)
 ```
 
+```
+import (
+	"fmt"
+	"github.com/ChainSafe/gossamer/pkg/scale"
+)
+
+func resultExample() {
+	// pass in zero or non-zero values of the types for Ok and Err cases
+	res := scale.NewResult(bool(false), string(""))
+
+	// set the OK case with a value of true, any values for OK that are not bool will return an error
+	err := res.Set(scale.OK, true)
+	if err != nil {
+		panic(err)
+	}
+
+	bytes, err := scale.Marshal(res)
+	if err != nil {
+		panic(err)
+	}
+
+	// [0x00, 0x01]
+	fmt.Printf("%v\n", bytes)
+
+	res1 := scale.NewResult(bool(false), string(""))
+
+	err = scale.Unmarshal(bytes, &res1)
+	if err != nil {
+		panic(err)
+	}
+
+	// res1 should be Set with OK mode and value of true
+	ok, err := res1.Unwrap()
+	if err != nil {
+		panic(err)
+	}
+
+	switch ok := ok.(type) {
+	case bool:
+		if !ok {
+			panic(fmt.Errorf("unexpected ok value: %v", ok))
+		}
+	default:
+		panic(fmt.Errorf("unexpected type: %T", ok))
+	}
+}
+
+```
+
 ### Varying Data Type
 
 A `VaryingDataType` is analogous to a Rust enum.  A `VaryingDataType` needs to be registered using the  `RegisterVaryingDataType` function with its associated `VaryingDataTypeValue` types.  `VaryingDataTypeValue` is an