const fileCopyBufSize = 524288 // 512k
func receiveFile(conn io.Reader, targetFile io.Writer, resForkFile io.Writer) error {
ffhBuf := make([]byte, 24)
const fileCopyBufSize = 524288 // 512k
func receiveFile(conn io.Reader, targetFile io.Writer, resForkFile io.Writer) error {
ffhBuf := make([]byte, 24)