Add RequestRestlike functor

Sources/ElixxirDAppsSDK/RequestRestlike.swift

+import Bindings
+import XCTestDynamicOverlay
+
+public struct RequestRestlike {
+  public var run: (Int, Data, RestlikeMessage, Data) throws -> RestlikeMessage
+
+  public func callAsFunction(
+    e2eId: Int,
+    recipient: Data,
+    request: RestlikeMessage,
+    paramsJSON: Data
+  ) throws -> RestlikeMessage {
+    try run(e2eId, recipient, request, paramsJSON)
+  }
+}
+
+extension RequestRestlike {
+  public static let live = RequestRestlike { e2dId, recipient, request, paramsJSON in
+    var error: NSError?
+    let responseData = BindingsRequestRestLike(
+      e2dId,
+      recipient,
+      try request.encode(),
+      paramsJSON,
+      &error
+    )
+    if let error = error {
+      throw error
+    }
+    guard let responseData = responseData else {
+      fatalError("BindingsRequestRestLike returned `nil` without providing error")
+    }
+    return try RestlikeMessage.decode(responseData)
+  }
+}
+
+extension RequestRestlike {
+  public static let unimplemented = RequestRestlike(
+    run: XCTUnimplemented("\(Self.self)")
+  )
+}