I'm not a fan of Hungarian notation, but C++ kind of needs it with its
implicit `this`. And of all the common options for this, I find
suffixing members with an underscore the least offensive one.
Apparently this can actually make a difference in some cases, and the
C++ Core Guideliens recommend doing this on all default constructors,
destructors, and all functions that can not throw (and thus also don't
allocate).
Bitwig prepends some data when passing an `IBStream*` to the plugin, and
when we do copy it iZotope Rx7 plugins cannot load their state (even if
we also copy over the same seek position). Not copying that preamble
fixes the issue, and it seems like it doesn't break anything.
And reset the seek position after reading. This new approach where we
also read from empty IBStreams to provide a perfect proxy would
otherwise cause plugins to crash in Bitwig when either loading or saving
state.
This allows presets to contain meta data about file names and the type
of preset.
Even though the docs don't mention that this is also relevant for
`getState()`, we should also implement it there so plugins can write
their own meta data.
Robbert van der Helm