Revert "Related: deb#766788 alloc on heap instead of stack"

This reverts commit 93fa8f69ea8759ec876f3683e93f47524899c00b.

I was under the impression that the data was copied in the ctor
but its not of course

Change-Id: I27d5c773052a42c76494edc820e3c56577900e8f