func SpanDecorator(decorator SpanDecoratorFunc) Option {
	return func(o *options) {
		o.decorator = decorator
	}
}
SpanDecorator binds a function that decorates gRPC Spans.
package otgrpc
import "github.com/opentracing/opentracing-go"
type Option func(o *options)
func LogPayloads() Option {
	return func(o *options) {
		o.logPayloads = true
	}
}
type SpanInclusionFunc func(
	parentSpanCtx opentracing.SpanContext,
	method string,
	req, resp interface{}) bool
func IncludingSpans(inclusionFunc SpanInclusionFunc) Option {
	return func(o *options) {
		o.inclusionFunc = inclusionFunc
	}
}
type SpanDecoratorFunc func(
	span opentracing.Span,
	method string,
	req, resp interface{},
	grpcError error)