qb: add support for USING TIMEOUT clause

In scylladb/scylla#7781 we added possibility to add timeout as part of USING spec.
This patch adds support for it by adding `Timeout` and `TimeoutNamed` functions to builders.

Fixes #194

qb/using.go

@@ -25,7 +25,10 @@ type using struct {
 	ttlName       string
 	timestamp     int64
 	timestampName string
-	using         bool
+	timeout       time.Duration
+	timeoutName   string
+
+	using bool
 }
 
 func (u *using) TTL(d time.Duration) *using {
@@ -55,6 +58,18 @@ func (u *using) TimestampNamed(name string) *using {
 	return u
 }
 
+func (u *using) Timeout(d time.Duration) *using {
+	u.timeout = d
+	u.timeoutName = ""
+	return u
+}
+
+func (u *using) TimeoutNamed(name string) *using {
+	u.timeout = 0
+	u.timeoutName = name
+	return u
+}
+
 func (u *using) writeCql(cql *bytes.Buffer) (names []string) {
 	u.using = false
 
@@ -79,6 +94,15 @@ func (u *using) writeCql(cql *bytes.Buffer) (names []string) {
 		names = append(names, u.timestampName)
 	}
 
+	if u.timeout != 0 {
+		u.writePreamble(cql)
+		fmt.Fprintf(cql, "TIMEOUT %s ", u.timeout)
+	} else if u.timeoutName != "" {
+		u.writePreamble(cql)
+		cql.WriteString("TIMEOUT ? ")
+		names = append(names, u.timeoutName)
+	}
+
 	return
 }