trace

type Config struct {
	ServiceName string
	Endpoint    string // e.g., "localhost:4317" or "https://host/path"
	Exporter    string // "otlp" or "stdout" (default: "stdout")
	SampleRate  float64
	Headers     map[string]string // Authorization headers
	Compression string            // "gzip"
	Timeout     time.Duration
}