Add Process ID to PatternEncoder

[naftulikay]

Allow specifying the process ID in PatternEncoder for including the current process ID in log formats.

[naftulikay]

I'm not sure what the issue is here, but it seems related to CircleCI pinning the Rust version on a version before the introduction of edition.

[estk]

@naftulikay I like this! In my open pr I've updated the rust build version 1.38 and it seems to be working. Would you back out the edition commit and we'll see if we can get this merged?

[naftulikay]

@estk I have removed the edition change as requested 👍

[estk]

@naftulikay great, I'm waiting on a review of #92 in order to get CI working again. Would you give it a look? After CI is fixed and this is re-run I'll merge.

[naftulikay]

@estk sure, are you looking for a review? seems like a massive amount of changes, though I'm grateful for all the hard work!

[estk]

@naftulikay ok, now that that is out of the way, can you rebase and rustfmt?

[naftulikay]

@estk rebased, do note that cargo fmt is modifying src/encode/writer/simple.rs and src/priv_io.rs, which are unmodified in this PR.

[estk]

@naftulikay thanks a million!
WRT the fmt modifying other files, I'll add fmt as part of the ci process soon.

[uwearzt]

Did a review (a little bit late ;) ). Change looks perfect, thanks to all for landing that!