Can't find method even though feature is in dependencies (reqwest)

    let client = reqwest::blocking::Client::new();
    let res = my_res!("https://removed")
        .body("the exact body that is sent")
        .send(), {
            return Err(String::from("failed send"));

is producing compiler error: no method named danger_accept_invalid_certs found for struct reqwest::blocking::RequestBuilder in the current scope

The documentation states "Available on crate features default-tls or native-tls or rustls-tls only."

and thus my cargo.toml attempt is currently:

native-tls = { version = "0.2.2", optional = true }
reqwest = { version = "0.11.11", features = ["native-tls-crate", "default-tls", "native-tls", "blocking"] }

but I cannot seem to find this method!

danger_accept_invalid_certs is a method on ClientBuilder which you linked to. The builder returned from is a RequestBuilder, as the error message notes.

In other words the setting is a property of the client, not the request. So you can't set it on an individual request.