Runtime not populating `APIGateway.V2.Request` properties

Expected behavior

I expected that I would be able to make a POST request with the payload "{ "number": 3 }" (from tutorial), and AWS would create the APIGateway.V2.Request object for me, storing the payload in the APIGateway.V2.Request.body property.

Actual behavior

It's as if the Lambda is expecting the consumer of the API to provide all the APIGateway.V2.Request properties in the payload. The specific error I got when attempting to call the Lambda is:

{ "errorType": "FunctionError", "errorMessage": "requestDecoding(Swift.DecodingError.keyNotFound(CodingKeys(stringValue: \"version\", intValue: nil), Swift.DecodingError.Context(codingPath: [], debugDescription: \"No value associated with key CodingKeys(stringValue: \\"version\\", intValue: nil) (\\"version\\").\", underlyingError: nil)))" }

If I provide values for all the APIGateway.V2.Request properties, then the Lambda works as expected: Successful payload:

{
        "routeKey":"POST /hello",
        "version":"2.0",
        "rawPath":"/hello",
        "body": "{\"number\": 3}",
        "stageVariables":{},
        "requestContext":{
            "timeEpoch":1587750461466,
            "domainPrefix":"hello",
            "accountId":"0123456789",
            "stage":"$default",
            "domainName":"hello.test.com",
            "apiId":"pb5dg6g3rg",
            "requestId":"LgLpnibOFiAEPCA=",
            "http":{
                "path":"/hello",
                "userAgent":"Paw/3.1.10 (Macintosh; OS X/10.15.4) GCDHTTPRequest",
                "method":"POST",
                "protocol":"HTTP/1.1",
                "sourceIp":"91.64.117.86"
            },
            "time":"24/Apr/2020:17:47:41 +0000"
        },
        "isBase64Encoded":false,
        "rawQueryString":"",
        "headers":{
            "host":"hello.test.com",
            "user-agent":"Paw/3.1.10 (Macintosh; OS X/10.15.4) GCDHTTPRequest",
            "content-length":"0"
        }
    }

Response:

{ "body": "{\"result\":9}", "statusCode": 200 }

Steps to reproduce

Create Swift Lambda using code below.
Build using Docker command in linked tutorial.
Package using script in linked tutorial.
Upload to AWS
Create a new API Gateway resource.
Add a POST method for it.
Use the Lambda for the POST method.
Click the new method in the API Gateway side pane.
Click the "Test" button.
Use the payload: { "number": 3 }
Run the test.

If possible, minimal yet complete reproducer code (or URL to code)

Here is the code in my main file:

import Foundation
import AWSLambdaRuntime
import AWSLambdaEvents
import AsyncKit

Lambda.run(APILambda())

public final class APILambda: LambdaHandler {

    public func handle(context: Lambda.Context, event: APIGateway.V2.Request, callback: @escaping (Result<APIGateway.V2.Response, Error>) -> Void) {
        guard let body=event.body else { callback(.failure(GeneralError())); return }
        do {
            let input: Input=try JSONDecoder().decode(Input.self, from: body)
            let output=Output(result: input.number * input.number)
            let data=try JSONEncoder().encode(output)
            let string=String(data: data, encoding: .utf8)!
            let response: APIGateway.V2.Response = .init(statusCode: .ok, headers: .none, body: string, isBase64Encoded: .none, cookies: .none)
            callback(.success(response))
        } catch let error {
            callback(.failure(error))
        }
    }

    public struct Input: Codable {
      let number: Double
    }

    public struct Output: Codable {
      let result: Double
    }

    private struct GeneralError: Error {}

    public typealias In = APIGateway.V2.Request
    public typealias Out = APIGateway.V2.Response
}

Here is my package.swift:

import PackageDescription

let package = Package(
    name: "API",
    platforms: [
        .macOS(.v10_15)
    ],
    products: [
        .executable(
            name: "API",
            targets: ["API"]),
    ],
    dependencies: [
        .package(url: "https://github.com/swift-server/swift-aws-lambda-runtime.git", .upToNextMajor(from:"0.5.0")),
        .package(url: "https://github.com/vapor/postgres-kit.git", .upToNextMajor(from:"2.0.0"))
    ],
    targets: [
        .target(
            name: "API",
            dependencies: [
                .product(name: "AWSLambdaRuntime", package: "swift-aws-lambda-runtime"),
                .product(name: "AWSLambdaEvents", package: "swift-aws-lambda-runtime"),
                .product(name: "PostgresKit", package: "postgres-kit")
            ])
    ]
)

SwiftAWSLambdaRuntime version/commit hash

0.5.2

Swift & OS version (output of `swift --version && uname -a`)

Apple Swift version 5.3.2 (swiftlang-1200.0.45 clang-1200.0.32.28) Target: x86_64-apple-darwin19.5.0 Darwin My-MBP-2.local 19.5.0 Darwin Kernel Version 19.5.0: Tue May 26 20:41:44 PDT 2020; root:xnu-6153.121.2~2/RELEASE_X86_64 x86_64

swift-server / swift-aws-lambda-runtime