function isNamedKeyCredential(credential) {
    return ((0, core_util_1.isObjectWithProperties)(credential, ["name", "key"]) &&
        typeof credential.key === "string" &&
        typeof credential.name === "string");
}
Create an instance of an AzureSASCredential for use
with a service client.

@param signature - The initial value of the shared access signature to use in authentication