# Description
Setting metadata on a byte stream converts it to a list stream. This PR
makes it so that `metadata set` does not alter its input besides the
metadata.
```nushell
open --raw test.json
| metadata set --content-type application/json
| http post https://httpbin.org/post
```
These sub-crates form both the foundation for Nu and a set of plugins which extend Nu with additional functionality.
Foundational libraries are split into two kinds of crates:
Core crates - those crates that work together to build the Nushell language engine
Support crates - a set of crates that support the engine with additional features like JSON support, ANSI support, and more.
Plugins are likewise also split into two types:
Core plugins - plugins that provide part of the default experience of Nu, including access to the system properties, processes, and web-connectivity features.
Extra plugins - these plugins run a wide range of different capabilities like working with different file types, charting, viewing binary data, and more.