rustc pls

error.rs

error[E0277]: the trait bound `std::ffi::OsString: std::borrow::Borrow<str>` is not satisfied
  --> src/echo.rs:12:52
   |
12 |                 if let Some(val) = state.variables.get(key) {
   |                                                    ^^^ the trait `std::borrow::Borrow<str>` is not implemented for `std::ffi::OsString`
   |
   = help: the following implementations were found:
             <std::ffi::OsString as std::borrow::Borrow<std::ffi::OsStr>>