Add support for Cassandra >= 3 with protocol version 4

driver/cassandra/cassandra.go

@@ -4,6 +4,7 @@ package cassandra
 import (
 	"fmt"
 	"net/url"
+	"strconv"
 	"strings"
 	"time"
 
@@ -40,10 +41,10 @@ const (
 )
 
 // Cassandra Driver URL format:
-// cassandra://host:port/keyspace
+// cassandra://host:port/keyspace?protocol=version
 //
 // Example:
-// cassandra://localhost/SpaceOfKeys
+// cassandra://localhost/SpaceOfKeys?protocol=4
 func (driver *Driver) Initialize(rawurl string) error {
 	u, err := url.Parse(rawurl)
 
@@ -52,6 +53,15 @@ func (driver *Driver) Initialize(rawurl string) error {
 	cluster.Consistency = gocql.All
 	cluster.Timeout = 1 * time.Minute
 
+	if len(u.Query().Get("protocol")) > 0 {
+		protoversion, err := strconv.Atoi(u.Query().Get("protocol"))
+		if err != nil {
+			return err
+		}
+
+		cluster.ProtoVersion = protoversion
+	}
+
 	// Check if url user struct is null
 	if u.User != nil {
 		password, passwordSet := u.User.Password()