code: func ToMap(ctx context.Context) map[string]interface{} {
  	if ctx == nil {
  		return map[string]interface{}{}
  	}
  	p := ctx.Value(constants.PropagateCtxKey)
  	if p != nil {
  		return p.(map[string]interface{})
  	}
  	return map[string]interface{}{}
  }
docs: // ToMap returns the values that will be propagated through RPC calls in map[string]interface{} format