ResolveFieldContext.cs

public class ResolveFieldContext<TSource>
    {
        public ResolveFieldContext();
        public ResolveFieldContext(ResolveFieldContext context);

        public ExecutionErrors Errors { get; set; }
        public Metrics Metrics { get; set; }
        public CancellationToken CancellationToken { get; set; }
        public Variables Variables { get; set; }
        public Fragments Fragments { get; set; }
        public Operation Operation { get; set; }
        public Document Document { get; set; }
        public ISchema Schema { get; set; }
        public TSource Source { get; set; }
        public object UserContext { get; set; }
        public object RootValue { get; set; }
        public Dictionary<string, object> Arguments { get; set; }
        public IObjectGraphType ParentType { get; set; }
        public IGraphType ReturnType { get; set; }
        public FieldType FieldDefinition { get; set; }
        public Language.AST.Field FieldAst { get; set; }
        public string FieldName { get; set; }
        public IEnumerable<string> Path { get; set; }
        public IDictionary<string, Language.AST.Field> SubFields { get; set; }

        public object GetArgument(System.Type argumentType, string name, object defaultValue = null);
        public TType GetArgument<TType>(string name, TType defaultValue = default);
        public bool HasArgument(string argumentName);
        [AsyncStateMachine(typeof(ResolveFieldContext<>.<TryAsyncResolve>d__82<>))]
        public Task<TResult> TryAsyncResolve<TResult>(Func<ResolveFieldContext<TSource>, Task<TResult>> resolve, Func<ExecutionErrors, Task<TResult>> error = null);
        public Task<object> TryAsyncResolve(Func<ResolveFieldContext<TSource>, Task<object>> resolve, Func<ExecutionErrors, Task<object>> error = null);
    }

Subscription.cs

private Probe ResolveProbe(ResolveFieldContext context)
        {
            var probe = context.Source as Probe;
            return context.Source as Probe;
        }