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: legacy.rs
    path of file: ./repos/grafbase/engine/crates/engine/src/context
    
    the code of the file until where you have to start completion: //! Contexts for resolving the legacy async_graphql derive based stuff...
//!
//! Hopefully one day we can delete this

use engine_parser::{
    types::{Field, SelectionSet},
    Positioned,
};
use ulid::Ulid;

use crate::{
    registry::type_kinds::OutputType, Context, ContextField, QueryEnv, QueryPath, QueryPathSegment, SchemaEnv,
};

#[derive(Clone)]
pub struct C
    
    pub fn with_field(&'a self, field: &'a Positioned<Field>) -> ContextField<'a> {
        let meta_field = self.ty.field(&field.node.name.node);

        let mut path = self.path.clone();
        path.push(field.node.response_key().node.as_str());

        ContextField {
            field: meta_field.expect("malformed query that should be validated before here"),
            parent_type: self
                .ty
                .try_into()
                .expect("have to be a selection set if were going into a field"),
            execution_id: Ulid::from_datetime(self.query_env.current_datetime.clone().into()),
            path,
            item: field,
            schema_env: self.schema_env,
            query_env: self.query_env,
        }
    }