move options to dedicated package

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

util/io/io.go

@@ -1,40 +0,0 @@
-// Package io is for io management
-package io // import "go.unistack.org/micro/v4/util/io"
-
-import (
-	"io"
-
-	"go.unistack.org/micro/v4/network/transport"
-)
-
-type rwc struct {
-	socket transport.Socket
-}
-
-func (r *rwc) Read(p []byte) (n int, err error) {
-	m := new(transport.Message)
-	if err := r.socket.Recv(m); err != nil {
-		return 0, err
-	}
-	copy(p, m.Body)
-	return len(m.Body), nil
-}
-
-func (r *rwc) Write(p []byte) (n int, err error) {
-	err = r.socket.Send(&transport.Message{
-		Body: p,
-	})
-	if err != nil {
-		return 0, err
-	}
-	return len(p), nil
-}
-
-func (r *rwc) Close() error {
-	return r.socket.Close()
-}
-
-// NewRWC returns a new ReadWriteCloser
-func NewRWC(sock transport.Socket) io.ReadWriteCloser {
-	return &rwc{sock}
-}