'受信バイト数が返る
Dim bytesRead As Integer = networkStream.EndRead(ar)
If bytesRead > 0 Then
'受信文字が有った
'受信部分だけ切り出す
Dim getByte As Byte() = New Byte(bytesRead - 1) {}
For i As Integer = 0 To bytesRead - 1
getByte(i) = buffer(i)
Next
''ここを追加 ↓↓↓↓↓
Thread.Sleep(300)
Do While networkStream.DataAvailable = True
Dim sbuffer = New Byte(9000) {}
Dim sLen As Integer
