Function invoke_set 

pub fn invoke_set(
    provider: &ProviderId,
    capability: &str,
    args: &[OsString],
    contract: &EnvContract,
    capture_json: bool,
) -> Result<SetInvocation>

Invoke <provider> __set <capability> ....

When capture_json is true, stdout is parsed as a CapabilityRunReport. Otherwise stdout/stderr stream directly.

Errors

Returns I/O errors from spawning the provider process.