examples/real-time-routeviews-kafka-openbmp.rs minor issues

[0x0ac]

So a couple of minor things here. Firstly, I am very new to rust so apologies if my assumptions are wrong. I took your code to compile and test, and I got thrown this error:

error[E0308]: mismatched types
   --> src/main.rs:44:30
    |
44  |         .with_offset_storage(Some(GroupOffsetStorage::Kafka))
    |          ------------------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `GroupOffsetStorage`, found `Option<GroupOffsetStorage>`
    |          |
    |          arguments to this method are incorrect
    |
    = note: expected enum `GroupOffsetStorage`
               found enum `Option<GroupOffsetStorage>`
note: method defined here
   --> /Users/owen/.cargo/registry/src/index.crates.io-6f17d22bba15001f/kafka-0.9.0/src/consumer/builder.rs:157:12
    |
157 |     pub fn with_offset_storage(mut self, storage: GroupOffsetStorage) -> Builder {
    |            ^^^^^^^^^^^^^^^^^^^

For more information about this error, try `rustc --explain E0308`.
error: could not compile `rv-check` (bin "rv-check") due to 1 previous error

I decided to remove the Some() wrapper, as it looks like the .with_offset_storage is expecting a GroupOffsetStorage directly, or maybe I am misunderstanding. However when I remove it, the code compiles and appears to work well.

in the example given you also have the pattern: r#"routeviews.amsix..*.bmp_raw"#

which is catching output from the 2 collectors:

    "routeviews.amsix.ams.39120.bmp_raw",
    "routeviews.amsix.ams.213241.bmp_raw",
    "routeviews.amsix.31019.bmp_raw",
    "routeviews.amsix.6908.bmp_raw",
    "routeviews.amsix.267613.bmp_raw",
    "routeviews.amsix.ams.140443.bmp_raw",

routeviews has 2 collectors at amsix : route-views.amsix.routeviews.org and amsix.ams.routeviews.org and I am pretty sure this is just the kind of topic collision we wanted to avoid :-)

thanks so much for your work on this Mingwei!!