Multi Processor Trace Example

In this example, the application in main.cc initializes and registers a tracer provider from the OpenTelemetry SDK. The TracerProvider is connected to two processor-exporter pipelines - for exporting simultaneously to StdoutSpanExporter and InMemorySpanExporter. The application then calls a foo_library which has been instrumented using the OpenTelemetry API. Resulting telemetry is directed to stdout through the StdoutSpanExporter, and saved as a variable (vector of spans) through InMemorySpanExporter.

See CONTRIBUTING.md for instructions on building and running the example.