Improve prepared statement performance

* Do not use bufio.Writer - use net.Conn directly
* Use byte slice instead of bytes.Buffer when building query message
* Use binary.BigEndian.* instead of binary.Write

example_value_transcoder_test.go

@@ -1,10 +1,8 @@
 package pgx_test
 
 import (
-	"encoding/binary"
 	"fmt"
 	"github.com/jackc/pgx"
-	"io"
 	"regexp"
 	"strconv"
 )
@@ -57,19 +55,15 @@ func decodePointFromText(mr *pgx.MessageReader, size int32) interface{} {
 	return p
 }
 
-func encodePoint(w io.Writer, value interface{}) error {
+func encodePoint(w *pgx.WriteBuf, value interface{}) error {
 	p, ok := value.(Point)
 	if !ok {
 		return fmt.Errorf("Expected Point, received %T", value)
 	}
 
 	s := fmt.Sprintf("point(%v,%v)", p.x, p.y)
+	w.WriteInt32(int32(len(s)))
+	w.WriteBytes([]byte(s))
 
-	err := binary.Write(w, binary.BigEndian, int32(len(s)))
-	if err != nil {
-		return err
-	}
-
-	_, err = io.WriteString(w, s)
-	return err
+	return nil
 }