Builders created with NewFixedBuilder were broken when used with BuilderContinuations. The length of the bytes written to the continuation would get added correctly to the parent, but the actual content would be discarded. For example, the BytesOrPanic() in TestFixedBuilderLengthPrefixed would return [00 08] instead of [00 08 ff ff ff ff ff ff ff ff]. Change-Id: I80837a9bf3562751addcb827274649d9f52fc79a Reviewed-on: https://go-review.googlesource.com/c/148882 Run-TryBot: Filippo Valsorda <filippo@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Adam Langley <agl@golang.org>