Function buffered_string_method_with_retry 

pub fn buffered_string_method_with_retry<F>(
    method_to_call: F,
    buffer_capacity: usize,
) -> Result<String, Error>
where
    F: FnMut(*mut c_char, i32, *mut UErrorCode) -> i32,

Helper for calling ICU4C uloc methods that require a resizable output string buffer.