You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: field.rs
    path of file: ./repos/gdnative/gdnative-derive/src/variant/attr
    
    the code of the file until where you have to start completion: use std::iter::FromIterator;

use proc_macro2::Span;
use syn::spanned::Spanned;

use crate::variant::Direction;

use super::AttrBuilder;

#[derive(Clone, Eq, PartialEq, Debug)]
pub struct FieldAttr {
    pub skip_to_variant: bool,
    pub skip_from_variant: bool,
    pub to_variant_with: Option<syn::Path>,
    pub from_variant_with: Option<syn::Path>,
}

impl FieldAttr {
    pub(crate)
    
    fn try_set_flag(&mut self, flag: &syn::Path) -> Result<(), syn::Error> {
        let name = flag
            .get_ident()
            .ok_or_else(|| generate_error_with_docs(flag.span(), "Invalid syntax"))?
            .to_string();

        impl_options! {
            self: self,
            match name.as_str() {
                skip_to_variant,
                skip_from_variant,
            }
        }

        #[allow(clippy::single_match)]
        match name.as_str() {
            "skip" => {
                self.skip_to_variant = true;
                self.skip_from_variant = true;
                return Ok(());
            }
            _ => {}
        }

        Err(generate_error_with_docs(
            flag.span(),
            "Missing macro arguments",
        ))
    }