[metrics-team] server-descriptor not readable (2018-02-08-11-05-00-server-descriptors has >30k descriptors)

[Katharina Haselhorst]

Hi Karsten,
> The main change is that metrics-lib will start providing descriptors
> from large descriptor files almost instantly, rather than all of them at
> once when it's done with the descriptor file.

Thanks a lot! Indeed, the total time to read the whole file does not 
change with the patch (I did a small comparison benchmark and in both 
cases it took about 1270 seconds to read the whole file on my machine - 
the big file which caused the problem...).
The difference is that the patched version delivers the descriptors with 
a constant rate of round 1000 descriptors in 40s. Which is great, since 
you don't get the impression that the application is stuck. And you can 
start to process the data earlier.

Regards, Kathi