message: The wasmer_metadata starts with a length.
  Fixes headless use case.
diff: @@ -185,6 +185,11 @@ impl NativeArtifact {
  };
  let serialized_data = bincode::serialize(&metadata).map_err(to_compile_error)?;
  + let mut metadata_binary = vec![0; 10];
  + let mut writable = &mut metadata_binary[..];
  + leb128::write::unsigned(&mut writable, serialized_data.len() as u64)
  + .expect("Should write number");
  + metadata_binary.extend(serialized_data);
  let obj_bytes = compiler.experimental_native_compile_module(
  &target,
  @@ -192,7 +197,7 @@ impl NativeArtifact {
  module_translation.as_ref().unwrap(),
  function_body_inputs,
  &metadata,
  - &serialized_data,
  + &metadata_binary
  )?;
  let filepath = {
  