OpenTelemetry-Go

This is a prototype intended to be modified into the opentelemetry-go implementation. The api directory here should be used as a starting point to introduce a new OpenTelemetry exporter, whereas the existing exporter/observer streaming model should be help verify the api

To run the examples, first build the stderr tracer plugin (requires Linux or OS X):

(cd ./experimental/streaming/exporter/stdout/plugin && make)
(cd ./experimental/streaming/exporter/spanlog/plugin && make)

Then set the OPENTELEMETRY_LIB environment variable to the .so file in that directory, e.g.,

OPENTELEMETRY_LIB=./experimental/streaming/exporter/stderr/plugin/stderr.so go run ./example/http/server/server.go

and

OPENTELEMETRY_LIB=./experimental/streaming/exporter/spanlog/plugin/spanlog.so go run ./example/http/client/client.go