add OpenTracing Shim usage (#1697)
add OpenTracing Shim usage (#1697)

* add OpenTracing Shim usage

Signed-off-by: Sergei Malafeev <58d0ab9b51c404152910167b6f877123a5c94faf@malafeev.org>

* specify 2 options to expose tracer

Signed-off-by: Sergei Malafeev <58d0ab9b51c404152910167b6f877123a5c94faf@malafeev.org>

* Update opentracing_shim/README.md

Co-authored-by: John Watson <d68442e18ce20d695ea66d3988492d75bf602243@gmail.com>

* Update opentracing_shim/README.md

Co-authored-by: John Watson <d68442e18ce20d695ea66d3988492d75bf602243@gmail.com>

* Update opentracing_shim/README.md

Co-authored-by: John Watson <d68442e18ce20d695ea66d3988492d75bf602243@gmail.com>

* Update opentracing_shim/README.md

Co-authored-by: John Watson <d68442e18ce20d695ea66d3988492d75bf602243@gmail.com>

* Update opentracing_shim/README.md

Co-authored-by: John Watson <d68442e18ce20d695ea66d3988492d75bf602243@gmail.com>

Co-authored-by: John Watson <d68442e18ce20d695ea66d3988492d75bf602243@gmail.com>
open-telemetry/opentelemetry-java,open-telemetry/opentelemetry-java,open-telemetry/opentelemetry-java