Error return type of TryFrom<Vec<u8>> for PrivateKeyDer<'_> doesn't impl std::error::Error

I tried the following:

    let key = PrivateKeyDer::try_from(std::fs::read(key)?)?;

And I get the error:

? couldn't convert the error: str: std::error::Error is not satisfied
the question mark operation (?) implicitly performs a conversion on the error value using the From trait
required for &str to implement std::error::Error
required for anyhow::Error to implement From<&str>

Unfortunately &str doesn't impl core::error::Error, so using it as the error return type in a try_from can cause users of the library some difficulty. It would be better to instead return a type that impls core::error::Error in the error value.

Search for the TryFrom<Vec> implementation for PrivateKeyDer<'_> and inspect its current error return type. Update the conversion so its error implements core::error::Error, then verify that the anyhow example in the issue can use ? without a conversion error.