[OSM-dev] PBF HeaderBlock optional?

[Anthony]

On Tue, Dec 21, 2010 at 11:08 AM, Scott Crosby <scott at sacrosby.com> wrote:
> On Mon, Dec 20, 2010 at 6:01 PM, Scott Crosby <scott at sacrosby.com> wrote:
>> Yes. That is an osmosis bug. That header block is required.
>
> I would like to clarify this slightly. There must be an OSMHeader
> block before the first OSMData block, however, the OSMHeader block
> does not have to be the first block in the file. Also, parsers should
> ignore fileblocks types that they do not understand.

And can there be more than one OSMHeader block, possibly with
different requirements, for instance concatenated streams?