Road to 1.0.

The C implementation of HDR Histogram is fairly stable now, but there are a number of pending changes that should really be in place before making it a 1.0 version. The 3 outstanding features I think that should be required are:

• packed arrays.
• resizable counts.
• double support.

However to complete this I think I would need to break the API to some degree. Mostly because the main struct is defined in the header which makes changing it potentially a breaking a change. To make future changes more flexible, I would like to make hdr_histogram an opaque point and hide the internal structure.

Feedback on how this may impact users would be appreciated. E.g. are there any users depending on stack allocation of the hdr_histogram?

Please reply to this issue if you have any issues or suggestions regarding the implementation for the next major revision of the HDR Histgoram.

Review the C implementation and the public hdr_histogram struct first, then assess how packed arrays, resizable counts, double support, and an opaque type would affect the API. Check whether users rely on stack allocation and document the compatibility decision and required scope before implementation.