[VOL-2193] Create mocks for Kafka Client and Etcd

This commit consists of:
1) A kafka client mock that implements the kafka client interface
under voltha-lib-go/pkg/kafka/client.go
2) An embedded Etcd server that runs in-process and represents an
Etcd server.

Change-Id: I52a36132568e08c596bb4136918bebcb654a3b99
diff --git a/vendor/github.com/json-iterator/go/reflect_native.go b/vendor/github.com/json-iterator/go/reflect_native.go
new file mode 100644
index 0000000..f88722d
--- /dev/null
+++ b/vendor/github.com/json-iterator/go/reflect_native.go
@@ -0,0 +1,453 @@
+package jsoniter
+
+import (
+	"encoding/base64"
+	"reflect"
+	"strconv"
+	"unsafe"
+
+	"github.com/modern-go/reflect2"
+)
+
+const ptrSize = 32 << uintptr(^uintptr(0)>>63)
+
+func createEncoderOfNative(ctx *ctx, typ reflect2.Type) ValEncoder {
+	if typ.Kind() == reflect.Slice && typ.(reflect2.SliceType).Elem().Kind() == reflect.Uint8 {
+		sliceDecoder := decoderOfSlice(ctx, typ)
+		return &base64Codec{sliceDecoder: sliceDecoder}
+	}
+	typeName := typ.String()
+	kind := typ.Kind()
+	switch kind {
+	case reflect.String:
+		if typeName != "string" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*string)(nil)).Elem())
+		}
+		return &stringCodec{}
+	case reflect.Int:
+		if typeName != "int" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*int)(nil)).Elem())
+		}
+		if strconv.IntSize == 32 {
+			return &int32Codec{}
+		}
+		return &int64Codec{}
+	case reflect.Int8:
+		if typeName != "int8" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*int8)(nil)).Elem())
+		}
+		return &int8Codec{}
+	case reflect.Int16:
+		if typeName != "int16" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*int16)(nil)).Elem())
+		}
+		return &int16Codec{}
+	case reflect.Int32:
+		if typeName != "int32" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*int32)(nil)).Elem())
+		}
+		return &int32Codec{}
+	case reflect.Int64:
+		if typeName != "int64" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*int64)(nil)).Elem())
+		}
+		return &int64Codec{}
+	case reflect.Uint:
+		if typeName != "uint" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*uint)(nil)).Elem())
+		}
+		if strconv.IntSize == 32 {
+			return &uint32Codec{}
+		}
+		return &uint64Codec{}
+	case reflect.Uint8:
+		if typeName != "uint8" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*uint8)(nil)).Elem())
+		}
+		return &uint8Codec{}
+	case reflect.Uint16:
+		if typeName != "uint16" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*uint16)(nil)).Elem())
+		}
+		return &uint16Codec{}
+	case reflect.Uint32:
+		if typeName != "uint32" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*uint32)(nil)).Elem())
+		}
+		return &uint32Codec{}
+	case reflect.Uintptr:
+		if typeName != "uintptr" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*uintptr)(nil)).Elem())
+		}
+		if ptrSize == 32 {
+			return &uint32Codec{}
+		}
+		return &uint64Codec{}
+	case reflect.Uint64:
+		if typeName != "uint64" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*uint64)(nil)).Elem())
+		}
+		return &uint64Codec{}
+	case reflect.Float32:
+		if typeName != "float32" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*float32)(nil)).Elem())
+		}
+		return &float32Codec{}
+	case reflect.Float64:
+		if typeName != "float64" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*float64)(nil)).Elem())
+		}
+		return &float64Codec{}
+	case reflect.Bool:
+		if typeName != "bool" {
+			return encoderOfType(ctx, reflect2.TypeOfPtr((*bool)(nil)).Elem())
+		}
+		return &boolCodec{}
+	}
+	return nil
+}
+
+func createDecoderOfNative(ctx *ctx, typ reflect2.Type) ValDecoder {
+	if typ.Kind() == reflect.Slice && typ.(reflect2.SliceType).Elem().Kind() == reflect.Uint8 {
+		sliceDecoder := decoderOfSlice(ctx, typ)
+		return &base64Codec{sliceDecoder: sliceDecoder}
+	}
+	typeName := typ.String()
+	switch typ.Kind() {
+	case reflect.String:
+		if typeName != "string" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*string)(nil)).Elem())
+		}
+		return &stringCodec{}
+	case reflect.Int:
+		if typeName != "int" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*int)(nil)).Elem())
+		}
+		if strconv.IntSize == 32 {
+			return &int32Codec{}
+		}
+		return &int64Codec{}
+	case reflect.Int8:
+		if typeName != "int8" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*int8)(nil)).Elem())
+		}
+		return &int8Codec{}
+	case reflect.Int16:
+		if typeName != "int16" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*int16)(nil)).Elem())
+		}
+		return &int16Codec{}
+	case reflect.Int32:
+		if typeName != "int32" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*int32)(nil)).Elem())
+		}
+		return &int32Codec{}
+	case reflect.Int64:
+		if typeName != "int64" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*int64)(nil)).Elem())
+		}
+		return &int64Codec{}
+	case reflect.Uint:
+		if typeName != "uint" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*uint)(nil)).Elem())
+		}
+		if strconv.IntSize == 32 {
+			return &uint32Codec{}
+		}
+		return &uint64Codec{}
+	case reflect.Uint8:
+		if typeName != "uint8" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*uint8)(nil)).Elem())
+		}
+		return &uint8Codec{}
+	case reflect.Uint16:
+		if typeName != "uint16" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*uint16)(nil)).Elem())
+		}
+		return &uint16Codec{}
+	case reflect.Uint32:
+		if typeName != "uint32" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*uint32)(nil)).Elem())
+		}
+		return &uint32Codec{}
+	case reflect.Uintptr:
+		if typeName != "uintptr" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*uintptr)(nil)).Elem())
+		}
+		if ptrSize == 32 {
+			return &uint32Codec{}
+		}
+		return &uint64Codec{}
+	case reflect.Uint64:
+		if typeName != "uint64" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*uint64)(nil)).Elem())
+		}
+		return &uint64Codec{}
+	case reflect.Float32:
+		if typeName != "float32" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*float32)(nil)).Elem())
+		}
+		return &float32Codec{}
+	case reflect.Float64:
+		if typeName != "float64" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*float64)(nil)).Elem())
+		}
+		return &float64Codec{}
+	case reflect.Bool:
+		if typeName != "bool" {
+			return decoderOfType(ctx, reflect2.TypeOfPtr((*bool)(nil)).Elem())
+		}
+		return &boolCodec{}
+	}
+	return nil
+}
+
+type stringCodec struct {
+}
+
+func (codec *stringCodec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	*((*string)(ptr)) = iter.ReadString()
+}
+
+func (codec *stringCodec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	str := *((*string)(ptr))
+	stream.WriteString(str)
+}
+
+func (codec *stringCodec) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*string)(ptr)) == ""
+}
+
+type int8Codec struct {
+}
+
+func (codec *int8Codec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if !iter.ReadNil() {
+		*((*int8)(ptr)) = iter.ReadInt8()
+	}
+}
+
+func (codec *int8Codec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteInt8(*((*int8)(ptr)))
+}
+
+func (codec *int8Codec) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*int8)(ptr)) == 0
+}
+
+type int16Codec struct {
+}
+
+func (codec *int16Codec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if !iter.ReadNil() {
+		*((*int16)(ptr)) = iter.ReadInt16()
+	}
+}
+
+func (codec *int16Codec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteInt16(*((*int16)(ptr)))
+}
+
+func (codec *int16Codec) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*int16)(ptr)) == 0
+}
+
+type int32Codec struct {
+}
+
+func (codec *int32Codec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if !iter.ReadNil() {
+		*((*int32)(ptr)) = iter.ReadInt32()
+	}
+}
+
+func (codec *int32Codec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteInt32(*((*int32)(ptr)))
+}
+
+func (codec *int32Codec) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*int32)(ptr)) == 0
+}
+
+type int64Codec struct {
+}
+
+func (codec *int64Codec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if !iter.ReadNil() {
+		*((*int64)(ptr)) = iter.ReadInt64()
+	}
+}
+
+func (codec *int64Codec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteInt64(*((*int64)(ptr)))
+}
+
+func (codec *int64Codec) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*int64)(ptr)) == 0
+}
+
+type uint8Codec struct {
+}
+
+func (codec *uint8Codec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if !iter.ReadNil() {
+		*((*uint8)(ptr)) = iter.ReadUint8()
+	}
+}
+
+func (codec *uint8Codec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteUint8(*((*uint8)(ptr)))
+}
+
+func (codec *uint8Codec) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*uint8)(ptr)) == 0
+}
+
+type uint16Codec struct {
+}
+
+func (codec *uint16Codec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if !iter.ReadNil() {
+		*((*uint16)(ptr)) = iter.ReadUint16()
+	}
+}
+
+func (codec *uint16Codec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteUint16(*((*uint16)(ptr)))
+}
+
+func (codec *uint16Codec) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*uint16)(ptr)) == 0
+}
+
+type uint32Codec struct {
+}
+
+func (codec *uint32Codec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if !iter.ReadNil() {
+		*((*uint32)(ptr)) = iter.ReadUint32()
+	}
+}
+
+func (codec *uint32Codec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteUint32(*((*uint32)(ptr)))
+}
+
+func (codec *uint32Codec) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*uint32)(ptr)) == 0
+}
+
+type uint64Codec struct {
+}
+
+func (codec *uint64Codec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if !iter.ReadNil() {
+		*((*uint64)(ptr)) = iter.ReadUint64()
+	}
+}
+
+func (codec *uint64Codec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteUint64(*((*uint64)(ptr)))
+}
+
+func (codec *uint64Codec) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*uint64)(ptr)) == 0
+}
+
+type float32Codec struct {
+}
+
+func (codec *float32Codec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if !iter.ReadNil() {
+		*((*float32)(ptr)) = iter.ReadFloat32()
+	}
+}
+
+func (codec *float32Codec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteFloat32(*((*float32)(ptr)))
+}
+
+func (codec *float32Codec) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*float32)(ptr)) == 0
+}
+
+type float64Codec struct {
+}
+
+func (codec *float64Codec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if !iter.ReadNil() {
+		*((*float64)(ptr)) = iter.ReadFloat64()
+	}
+}
+
+func (codec *float64Codec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteFloat64(*((*float64)(ptr)))
+}
+
+func (codec *float64Codec) IsEmpty(ptr unsafe.Pointer) bool {
+	return *((*float64)(ptr)) == 0
+}
+
+type boolCodec struct {
+}
+
+func (codec *boolCodec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if !iter.ReadNil() {
+		*((*bool)(ptr)) = iter.ReadBool()
+	}
+}
+
+func (codec *boolCodec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	stream.WriteBool(*((*bool)(ptr)))
+}
+
+func (codec *boolCodec) IsEmpty(ptr unsafe.Pointer) bool {
+	return !(*((*bool)(ptr)))
+}
+
+type base64Codec struct {
+	sliceType    *reflect2.UnsafeSliceType
+	sliceDecoder ValDecoder
+}
+
+func (codec *base64Codec) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	if iter.ReadNil() {
+		codec.sliceType.UnsafeSetNil(ptr)
+		return
+	}
+	switch iter.WhatIsNext() {
+	case StringValue:
+		src := iter.ReadString()
+		dst, err := base64.StdEncoding.DecodeString(src)
+		if err != nil {
+			iter.ReportError("decode base64", err.Error())
+		} else {
+			codec.sliceType.UnsafeSet(ptr, unsafe.Pointer(&dst))
+		}
+	case ArrayValue:
+		codec.sliceDecoder.Decode(ptr, iter)
+	default:
+		iter.ReportError("base64Codec", "invalid input")
+	}
+}
+
+func (codec *base64Codec) Encode(ptr unsafe.Pointer, stream *Stream) {
+	if codec.sliceType.UnsafeIsNil(ptr) {
+		stream.WriteNil()
+		return
+	}
+	src := *((*[]byte)(ptr))
+	encoding := base64.StdEncoding
+	stream.writeByte('"')
+	if len(src) != 0 {
+		size := encoding.EncodedLen(len(src))
+		buf := make([]byte, size)
+		encoding.Encode(buf, src)
+		stream.buf = append(stream.buf, buf...)
+	}
+	stream.writeByte('"')
+}
+
+func (codec *base64Codec) IsEmpty(ptr unsafe.Pointer) bool {
+	return len(*((*[]byte)(ptr))) == 0
+}