You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: main.go
    path of file: ./repos/mirrord/mirrord/layer/tests/apps/lseek_go
    
    the code of the file until where you have to start completion: package main

import (
	"C"
	"fmt"
	"os"
)

const TEXT = "Pineapples."

// Tests: SYS_lseek
fun
    
func main() {
    fileName := "/app/test.txt"
	file, err := os.Open(fileName)
	if err != nil {
		panic(err)
	}
	buf := make([]byte, len(TEXT))
	var offset int64 = 4
	file.Seek(offset, 1) // 1 means the offset is from the start.
	amount_read, err := file.Read(buf)
	if err != nil {
		panic(err)
	}
	if string(buf[:amount_read]) != TEXT[offset:] {
		err := fmt.Errorf("Expected %s, got %s", TEXT[offset:], string(buf))
		panic(err)
	}
	// Not closing the file here because Go does not wait for the detour to complete before returning here from `Close`,
	// So the Close message might not be sent by the layer before the app exits. So in order to keep this test
	// deterministic, we don't close here. There is a dedicated close test for testing the close hook.
}