tx.go
func WithTx(ctx context.Context, t Tx) context.Context {
	return context.WithValue(ctx, txKey, t)
}
func WithTx(ctx context.Context, t Tx) context.Context {
	return context.WithValue(ctx, txKey, t)
}
func WithTx ( ctx context . Context , t Tx ) context . Context { return context . WithValue ( ctx , txKey , t ) }
// WithTx inserts a newrelic.Tx into the provided context.
WithTx inserts a newrelic . Tx into the provided context .