Some calls like json.Encoder.Encode mask the number of bytes written to
an io.Writer. The solution provides a wrapper io.Writer around the
actual io.Writer that allows multiple calls to Write to be considered as
one and allow access to this count.
Signed-off-by: Pierre Wacrenier <pierre.wacrenier@gmail.com>
Upstream-commit: 0cd30cf3991de1b491cac3c0cecdc976f0098f29
Component: engine