func TLSCertFromFiles(certFile, keyFile string) TLSCertProvider {
	return func() (tls.Certificate, error) {
		return tls.LoadX509KeyPair(certFile, keyFile)
	}
}
TLSCertFromFiles returns a provider that returns a tls.Certificate by loading an X509 key pair from the files in the
specified locations.
package tlsconfig
import (
	"crypto/tls"
	"crypto/x509"
	"fmt"
	"io/ioutil"
)
var defaultCipherSuites = []uint16{
	tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
	tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
	tls.TLS_RSA_WITH_AES_256_GCM_SHA384,
	tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
	tls.TLS_RSA_WITH_AES_256_CBC_SHA,
}