What could be.go

package main

import (
    "io"
    "os"
)

type nopCloser[T io.Reader | io.Writer] struct {
    T
}

func NopCloser[T io.Reader | io.Writer](r T) nopCloser[T] {
	return nopCloser[T]{r}
}

func (nopCloser[T]) Close() error { return nil }


func main() {
    a := NopCloser(os.Stdin)
    _, err := a.Seek(10, 1)
    panic(err)
}