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: to_winmd.rs
    path of file: ./repos/windows-rs/crates/libs/bindgen/src/rdl
    
    the code of the file until where you have to start completion: use super::*;
use crate::winmd::writer;

// TODO: store span in winmd so that errors resolving type references can be traced back to file/line/column
use std::collections::HashMap;
//use syn::spanned::Spanned;

// TODO: this creates a temporary in-memory winmd used to treat the IDL content uniformly as metadata.
// The winmd_to_winmd does the harder job of validating and producing canonical winmd for public consumption.

pub fn rdl_to_winmd(file: &Fi
    
fn write_struct(writer: &mut winmd::Writer, namespace: &str, name: &str, member: &Struct) {
    let mut flags = metadata::TypeAttributes::Public | metadata::TypeAttributes::Sealed | metadata::TypeAttributes::SequentialLayout;

    if member.winrt {
        flags |= metadata::TypeAttributes::WindowsRuntime
    }

    let extends = writer.insert_type_ref("System", "ValueType");

    writer.tables.TypeDef.push(winmd::TypeDef {
        Extends: extends,
        FieldList: writer.tables.Field.len() as u32,
        MethodList: writer.tables.MethodDef.len() as u32,
        Flags: flags.0,
        TypeName: writer.strings.insert(name),
        TypeNamespace: writer.strings.insert(namespace),
    });

    for field in &member.fields {
        let flags = metadata::FieldAttributes::Public;
        let ty = syn_type(namespace, &[], &field.ty);
        let signature = writer.insert_field_sig(&ty);

        writer.tables.Field.push(winmd::Field { Flags: flags.0, Name: writer.strings.insert(&field.name), Signature: signature });
    }
}