Fix variable buffer size

The switch to `io.Copy()` to pump the data to the soundbox devices
removed the control over the buffer size of this copy action.

While for generic copy actions it is even an advantage when a big buffer
is used this is a problem for the soundbox use case. A big buffer used
during copy means that the first soundbox device gets audio data
significantly earlier than the later ones since `io.MultiWriter()` works
sequentially.

Thus this commit switches to `io.CopyBuffer()` where a buffer has to
provided. For that purpose the same buffer size is used as before the
refactoring to use `io.Copy()`.

1 files changed, 2 insertions, 1 deletions

diff --git a/soundbox/streaming.go b/soundbox/streaming.go
index 1a2d89e..357fa30 100644
--- a/soundbox/streaming.go
+++ b/soundbox/streaming.go
@@ -33,7 +33,8 @@ func streamContext(ctx context.Context, r io.Reader, targets []net.HardwareAddr)
 
 	mw := io.MultiWriter(writers...)
 
-	_, err := io.Copy(mw, r)
+	buf := make([]byte, bufferSize)
+	_, err := io.CopyBuffer(mw, r, buf)
 
 	return err
 }