Macro rust_icu_common::buffered_string_method_with_retry

macro_rules! buffered_string_method_with_retry {
    ($method_name:ident, $buffer_capacity:expr,
     [$($before_arg:ident: $before_arg_type:ty,)*],
     [$($after_arg:ident: $after_arg_type:ty,)*]) => { ... };
}

Generates a method to wrap ICU4C uloc methods that require a resizable output string buffer.

The various uloc methods of this type have inconsistent signature patterns, with some putting all their input arguments before the buffer and its capacity, and some splitting the input arguments.

Therefore, the macro supports input arguments in both positions.

For an invocation of the form

buffered_string_method_with_retry!(
    my_method,
    BUFFER_CAPACITY,
    [before_arg_a: before_type_a, before_arg_b: before_type_b,],
    [after_arg_a: after_type_a, after_arg_b: after_type_b,]
);

the generated method has a signature of the form

fn my_method(
    method_to_call: unsafe extern "C" fn(
        before_type_a,
        before_type_b,
        *mut raw::c_char,
        i32,
        after_type_a,
        after_type_b,
        *mut sys::UErrorCode,
    ) -> i32,
    before_arg_a: before_type_a,
    before_arg_b: before_type_b,
    after_arg_a: after_type_a,
    after_arg_b: after_type_b
) -> Result<String, common::Error> {}