While a lambda is still processing (archive unpacking etc), the lambda state should be set to "Pending" (currently "Active") and invocations to that lambda should fail (currently, it can end up in a inconsistent state in this case, like lambdas being executed without layers).

Lambda state should reflect the current internal state, and invocations should fail if not active.
return jsonify({})
@app.route("/2019-09-25/functions/<function>/event-invoke-config", methods=["PUT", "POST"])
def put_function_event_invoke_config(function):
    
    """Add/Updates the configuration for asynchronous invocation for a function
    ---
    operationId: PutFunctionEventInvokeConfig | UpdateFunctionEventInvokeConfig
    parameters:
        - name: 'function'
          in: path
        - name: 'qualifier'
          in: path
        - name: 'request'
          in: body
    """
    region = LambdaRegion.get()
    data = json.loads(to_str(request.data))
    function_arn = func_arn(function)
    lambda_obj = region.lambdas.get(function_arn)
    if not lambda_obj:
        return not_found_error("Unable to find Lambda ARN: %s" % function_arn)
    if request.method == "PUT":
        response = lambda_obj.clear_function_event_invoke_config()
    response = lambda_obj.put_function_event_invoke_config(data)
    return jsonify(
        {
            "LastModified": response.last_modified.strftime(DATE_FORMAT),
            "FunctionArn": str(function_arn),
            "MaximumRetryAttempts": response.max_retry_attempts,
            "MaximumEventAgeInSeconds": response.max_event_age,