## Description
Describe the issue as clearly as possible. Issues are meant for bug reports and feature requests. The issue should contain enough information for a developer to put together a solution.

If this is a general question, please post to the [forums](http://discourse.mc-stan.org).

## Example
For **bug reports**:

- please provide an example that shows the bug
- if it's not possible to reproduce the bug with an example, please include a description of how you discovered the issue


For **feature requests**:

- please provide an example that shows how the feature should work
- describe the expected behavior if the feature exists


## Expected Output
Please provide the expected output.

If this is a **bug report**, show what you expected to happen. Please also show what currently happens.

If this is a **feature request**, show what you expect to happen if the feature exists.


#### Current Version:
v2.19.0
