title: Cargo registry directory
body: <p>How do I specify another directory where cargo keeps the unpacked sources, e.g. on Windows this is <code>%userprofile%/.cargo/registry/src</code>?</p>
  
  <p>I working that is going to be a collection of crates like: </p>
  
  <pre><code>myproject-tree/
    foo
      +Cargo.toml
    bar
      +Cargo.toml
  </code></pre>
  
  <p>So I would like the dependencies to be loaded in unpacked somewhere near the <code>myproject-tree</code> directory, e.g. </p>
  
  <pre><code>myproject-tree/
  cargo-cache/
  </code></pre>
  
  <p>I think that would make it easier to inspect the code of dependencies (e.g. in the code editors with file tree UI). I can see that there is CARGO_HOME that seems like it has something like this, but it does not look convenient, e.g. each time I am going to work with <code>myproject-tree</code> I have to set it.</p>