add dotnet-collect command that uses EventPipe

[analogrelay]

Collects Event Traces from .NET processes

Usage: dotnet-collect [options]

Options:
  -c|--config-path <CONFIG_PATH>  The path of the EventPipe config file to write, must be named [AppName].eventpipeconfig and be in the base directory for a managed app.
  -p|--process-id <PROCESS_ID>    Filter to only the process with the specified process ID.
  -o|--output <OUTPUT_DIRECTORY>  The directory to write the trace to. Defaults to the current working directory.
  --buffer <BUFFER_SIZE_IN_MB>    The size of the in-memory circular buffer in megabytes.
  --provider <PROVIDER_SPEC>      An EventPipe provider to enable. A string in the form '<provider name>:<keywords>:<level>'. Can be specified multiple times to enable multiple providers.
  -?|-h|--help                    Show help information

The -c|--config-path is the only required option (though no providers will be enabled ;)). As an example, to collect all events from the .NET Runtime event source:

dotnet collect -c ./path/to/AppName.eventpipeconfig --provider Microsoft-Windows-DotNETRuntime

Files will be written to the output directory (-o|--output, defaults to current working directory) in the form [appname].[processId].netperf and can be viewed in PerfView.

Fixes #32

[analogrelay]

FYI https://github.com/dotnet/coreclr/issues/20454 is tracking an issue where the eventpipeconfig file has to be next to dotnet.exe rather than next to the managed entry point dll.

[davidfowl]

The only thing wrong with this is your formatting

[analogrelay]

I'llformatyou