func Dial(addr string) (*Client, error) {
	conn, err := net.Dial("tcp", addr)
	if err != nil {
		return nil, err
	}
	return NewClient(conn)
}
Dial creates an unsecured connection to the POP3 server at the given address
and returns the corresponding Client.
package pop3
import (
	"bufio"
	"crypto/tls"
	"errors"
	"fmt"
	"net"
	"strconv"
	"strings"
)
type Client struct {
	conn net.Conn
	bin  *bufio.Reader
}