Imports go.opentelemetry.io/otel go.opentelemetry.io/otel/exporters/zipkin go.opentelemetry.io/otel/sdk/resource go.opentelemetry.io/otel/sdk/trace go.opentelemetry.io/otel/semconv/v1.21.0 go.opentelemetry.io/otel/trace Standard library imports context flag log os