Use the GetSessionMetaDataCount method to retrieve the total number of metadata arrays available in the session this frame occurred in.
Profiler data can contain frames from different sessions.
When there are multiple Profiler.EmitSessionMetaData calls in the same frame, it results in multiple metadata arrays that are associated with the frame for a given id, tag pair. This information can be used to write data to the stream in small portions, which reduces the amount of memory needed to hold generated data.
Use id to identify the metadata from your project or package.
Use tag to distinguish between different data streams.
Additional resources: GetSessionMetaData, Profiler.EmitSessionMetaData.