Function with_extra_roots 

pub fn with_extra_roots(b: ClientBuilder) -> ClientBuilder

Extend a reqwest ClientBuilder with PEM certs from the NODE_EXTRA_CA_CERTS env var (falls back to SSL_CERT_FILE).

Unset, empty, unreadable, or unparseable paths are logged as warn and the builder is returned unchanged. This mirrors how Node’s TLS layer treats NODE_EXTRA_CA_CERTS as a best-effort extension - a malformed bundle doesn’t kill the program.