Function apply_datadog_env_vars 

pub fn apply_datadog_env_vars(
    base: &mut Value,
    vars: impl IntoIterator<Item = (String, String)>,
    overwrite: bool,
) -> Result<(), String>

Reads every modeled Datadog key from explicitly provided environment variable name/value pairs.

Identical to apply_datadog_env except for where the variables come from. Tests use this to avoid depending on the ambient process environment.

Errors

Returns a message naming the environment variable when its value is malformed for the key’s declared shape.