I want to retrieve PEM encoded server certificate in golang. The output should be the same as we'd get with

openssl s_client -showcerts -connect example.com:443 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p'

I tried in go

package main

import (
    "crypto/tls"
    "crypto/x509"
    "encoding/pem"
    "fmt"
)

func main() {
    fmt.Println(getCertificate("example.com"))
}

func getCertificate(domain string) string {

    conn, err := tls.Dial("tcp", fmt.Sprintf("%v:443", domain), nil)
    if err != nil {
        panic(err.Error())
    }
    defer conn.Close()
    certificate := conn.ConnectionState().PeerCertificates[0]

    x509AsBytes, err := x509.MarshalPKIXPublicKey(certificate.PublicKey)
    if err != nil {
        panic(err.Error())
    }

    pem := pem.EncodeToMemory(&pem.Block{
        Type:  "CERTIFICATE",
        Bytes: x509AsBytes,
    })

    return string(pem)
}

I get

-----BEGIN CERTIFICATE-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAoDBCVtcLoRG58wvszPJM
sG8TAmvPB/OF8EKPxVSYgW56kzi2+kZCs1zmyTtZk2EkQyD1eonJd63/h8gI24b1
3GF1ll/c8AjKOrleD/o3fGVqyggnHp3YCj+eENtFJZoDcrr1J9mw6zbUkzmMEWxf
MxRY5cCIxR96IRTM0qdfHHMf2QMgbnoI7xdO474owE/gcWMhBHePj0sr6Auivpd+
UG+4Ozdjf6QMmf+WosN/ynwhuv2Q0T8FpDRw1oSOpQDcKXz9lstDrjmPLcat2MId
m+RfnFGci/5tSWJbx80eGJbOxioHt3GAYHKsVxIAkEMPI76pcHHW5XuFo00FiCHH
IwIDAQAB
-----END CERTIFICATE-----

I want to get the same as with openssl s_client -showcerts

-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----