How to search for a substring within a byte slice using the bytes package in Go?

To search for a substring within a byte slice using the bytes package in Go, you can use the Index function provided by the package. Here's an example:

package main

import (
	"bytes"
	"fmt"
)

func main() {
	// Example byte slice
	byteSlice := []byte("Hello, World!")

	// Substring to search for
	substring := []byte("World")

	// Find the index of the substring in the byte slice
	index := bytes.Index(byteSlice, substring)

	if index != -1 {
		fmt.Printf("Substring '%s' found at index %d\n", string(substring), index)
	} else {
		fmt.Printf("Substring '%s' not found\n", string(substring))
	}
}

In this example, we define a byte slice byteSlice and a substring substring that we want to search for in byteSlice. We then use the Index method of the bytes package to find the index of the first occurrence of the substring within the byte slice. If the index is not -1, it means that the substring was found, and we can print the index. Otherwise, we print a message indicating that the substring was not found.