Using Custom Data Connector to read Local .txt File

I am trying to read the contents of a local text, but when I try to use my custom connector in Power BI, it keeps giving me the error "Please specify how to connect". I have tried the different authentication types but none of them have worked.

[DataSource.Kind = "LocalFile", Publish = "LocalFile.Publish"]
shared LocalFile.Contents  = () =>
    let
    path = "C:\Users\User\Documents\key.txt",
    ttemp = File.Contents("C:\Users\User\Documents\key.txt"),
    token = Text.FromBinary(ttemp),
    headers = [#"Content-Type"="application/json", #"Authorization"=token],
    result = Json.Document(Web.Contents(url, [Headers = headers])),
    in
        result;

LocalFile = [
    Authentication = [
        UsernamePassword = [],
        Windows = [],
        Anonymous = []
    ]
];

I'm not sure how to resolve this issue. I am able to read a local file by creating a Windows credential with the path to the file for use in the .pq file, but I can't find this option in the data connector itself.