Function call 

pub fn call(
    runtime: &str,
    module_name: &str,
    module: Value,
    member: &str,
    arguments: Value,
    callback: Callback<'_>,
) -> Result<Value, String>

runtime.module.member(arguments…) (arguments null: the member itself, read): the value the runtime answered, or its error as runtime module.member: error; module is a module’s name or a handle, module_name how errors name it