Reassemble partial packets on the client

The sender's network stack assembles tcp packets without regard for
write boundaries, so the receiver has to be prepared for partial reads.

tcpdelay.go

@@ -2,8 +2,8 @@ package main
 
 import (
 	"encoding/binary"
-	"gopkg.in/alecthomas/kingpin.v2"
 	"fmt"
+	"gopkg.in/alecthomas/kingpin.v2"
 	"log"
 	"net"
 	"os"
@@ -63,13 +63,17 @@ func tcpdelayClient() {
 	o := 0
 	buffer := make([]byte, 1024)
 	for {
-		n, err := conn.Read(buffer)
+		n := 0
+		for n < len(buffer) {
+			nr, err := conn.Read(buffer[n:])
 			if err != nil {
-			log.Fatal("Cannot read from ", *serverAddress, err)
+				log.Fatal("Cannot read from ", *serverAddress, err.Error())
 			}
-		if n != len(buffer) {
+			if nr <= 0 {
 				log.Fatal("Read ", n, " bytes intead of ", len(buffer))
 			}
+			n += nr
+		}
 		tr := time.Now().UnixNano()
 		if string(buffer[0:8]) != "tcpdelay" {
 			log.Fatal("Unexpected magic ", buffer[0:8])