It would appear that ostream::write needs a size64_t... stream sizes are being returned in size64_t and taken as size_t.
Here's my example...
Here's my example...
return Concurrency::streams::file_stream<uint8_t>::open_ostream(fullname)
.then([=](Concurrency::streams::ostream stream)
{
std::stringstream strstr;
jsv.serialize(strstr);
auto strx = Concurrency::streams::stringstream::open_istream(strstr.str());
return stream.write(strx.streambuf(), static_cast<size_t>(strx.streambuf().size()));
});