I'm repeatedly getting the following error when trying to launch the the Google Native Ads in my Flutter iOS version. When I run the exact same code for Android Studio everything works as expected. Here is the error that's thrown...

*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UIView 0x7fe74b6ba4c0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key advertiserView.'
***

Here is the code I've written for Flutter that works for Android....

  Future adBuilder() async {
    // TODO: Create a NativeAd instance
     _ad = NativeAd(
      adUnitId: NativeAd.testAdUnitId,
      factoryId: 'listTile',
      request: AdRequest(keywords: ['app']),
      listener: NativeAdListener(
        onAdLoaded: (_) {
          setState(() {
            _isAdLoaded = 'loaded';
          });
        },
        onAdFailedToLoad: (ad, error) {
          // Releases an ad resource when it fails to load
          Future<void>.delayed(Duration(seconds: 3), () => adBuilder());
          setState(() {
            _isAdLoaded = 'failed';
          });
        },
        onAdImpression: (_) {
          Future<void>.delayed(Duration(seconds: 1), () => adBuilder());
        }
      ),
    );
     _searchAd = _ad;
     _searchAd.load();
  }

Here is what my iOS xib file looks like....

<?xml version="1.0" encoding="UTF-8"?>
<document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="17156" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" colorMatched="YES">
    <device id="retina4_7" orientation="portrait" appearance="light"/>
    <dependencies>
        <deployment version="2048" identifier="iOS"/>
        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="17125"/>
        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
    </dependencies>
    <objects>
        <placeholder placeholderIdentifier="IBFilesOwner" id="-1" userLabel="File's Owner"/>
        <placeholder placeholderIdentifier="IBFirstResponder" id="-2" customClass="UIResponder"/>
        <view contentMode="scaleToFill" id="iN0-l3-epB" customClass="GADUnifiedNativeAdView">
            <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
            <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
            <subviews>
                <imageView userInteractionEnabled="NO" contentMode="scaleAspectFit" horizontalHuggingPriority="251" verticalHuggingPriority="251" translatesAutoresizingMaskIntoConstraints="NO" id="iNa-bH-h1m">
                    <rect key="frame" x="15" y="15.5" width="40" height="40"/>
                    <constraints>
                        <constraint firstAttribute="height" constant="40" id="ICz-3W-FQf"/>
                        <constraint firstAttribute="width" constant="40" id="vY6-8D-xIn"/>
                    </constraints>
                </imageView>
                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Advertiser" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="GTT-Yh-eSq">
                    <rect key="frame" x="63" y="38.5" width="66.5" height="17"/>
                    <fontDescription key="fontDescription" type="system" pointSize="14"/>
                    <color key="textColor" systemColor="darkTextColor"/>
                    <nil key="highlightedColor"/>
                </label>
                <imageView userInteractionEnabled="NO" contentMode="scaleToFill" horizontalHuggingPriority="251" verticalHuggingPriority="251" placeholderIntrinsicWidth="100" placeholderIntrinsicHeight="17" translatesAutoresizingMaskIntoConstraints="NO" id="2Of-AP-0h9">
                    <rect key="frame" x="129.5" y="38.5" width="100" height="17"/>
                    <constraints>
                        <constraint firstAttribute="height" constant="17" id="jBW-Cz-Kyc"/>
                        <constraint firstAttribute="width" constant="100" id="sXk-zk-NI0"/>
                    </constraints>
                </imageView>
                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" verticalCompressionResistancePriority="751" text="Body that is really really long and can take up to two lines or sometimes even more." textAlignment="justified" lineBreakMode="tailTruncation" numberOfLines="0" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="PEQ-D9-2Vv">
                    <rect key="frame" x="15" y="63.5" width="350" height="33.5"/>
                    <fontDescription key="fontDescription" type="system" pointSize="14"/>
                    <color key="textColor" systemColor="darkTextColor"/>
                    <nil key="highlightedColor"/>
                </label>
                <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="E5w-YA-UY8">
                    <rect key="frame" x="318" y="259.5" width="47" height="34"/>
                    <fontDescription key="fontDescription" type="system" pointSize="18"/>
                    <state key="normal" title="Install">
                        <color key="titleShadowColor" red="0.5" green="0.5" blue="0.5" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                    </state>
                </button>
                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Price" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="Ysb-of-cat">
                    <rect key="frame" x="230" y="268" width="33" height="17"/>
                    <fontDescription key="fontDescription" type="system" pointSize="14"/>
                    <color key="textColor" systemColor="darkTextColor"/>
                    <nil key="highlightedColor"/>
                </label>
                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Store" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="hwF-UL-Q8H">
                    <rect key="frame" x="273" y="268" width="35" height="17"/>
                    <fontDescription key="fontDescription" type="system" pointSize="14"/>
                    <color key="textColor" systemColor="darkTextColor"/>
                    <nil key="highlightedColor"/>
                </label>
                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" verticalHuggingPriority="251" horizontalCompressionResistancePriority="751" text="Headline" textAlignment="justified" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="beR-eV-DX1">
                    <rect key="frame" x="63" y="10" width="297" height="20.5"/>
                    <constraints>
                        <constraint firstAttribute="height" constant="20.5" id="6r8-Hu-d0y"/>
                    </constraints>
                    <fontDescription key="fontDescription" type="system" pointSize="17"/>
                    <color key="textColor" systemColor="darkTextColor"/>
                    <nil key="highlightedColor"/>
                </label>
                <view contentMode="scaleAspectFit" translatesAutoresizingMaskIntoConstraints="NO" id="fNp-yu-K4i" customClass="GADMediaView">
                    <rect key="frame" x="62.5" y="102" width="250" height="150"/>
                    <constraints>
                        <constraint firstAttribute="height" priority="750" constant="150" id="71m-kn-7Ug"/>
                        <constraint firstAttribute="width" constant="250" id="e3T-fD-di4"/>
                    </constraints>
                </view>
                <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Ad" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="lp1-oz-XOs">
                    <rect key="frame" x="0.0" y="0.0" width="15" height="15"/>
                    <color key="backgroundColor" red="1" green="0.80000001190000003" blue="0.40000000600000002" alpha="1" colorSpace="calibratedRGB"/>
                    <constraints>
                        <constraint firstAttribute="width" relation="greaterThanOrEqual" constant="15" id="Twa-Vk-uWQ"/>
                        <constraint firstAttribute="height" constant="15" id="k8m-kJ-CF5"/>
                    </constraints>
                    <fontDescription key="fontDescription" type="system" weight="semibold" pointSize="11"/>
                    <color key="textColor" white="1" alpha="1" colorSpace="calibratedWhite"/>
                    <nil key="highlightedColor"/>
                </label>
            </subviews>
            <color key="backgroundColor" red="1" green="0.98303861469999998" blue="0.92887652860000003" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
            <constraints>
                <constraint firstItem="GTT-Yh-eSq" firstAttribute="leading" secondItem="beR-eV-DX1" secondAttribute="leading" id="0sB-Mk-EU6"/>
                <constraint firstItem="lp1-oz-XOs" firstAttribute="top" secondItem="iN0-l3-epB" secondAttribute="top" id="3lA-qv-Nkc"/>
                <constraint firstItem="Ysb-of-cat" firstAttribute="leading" relation="greaterThanOrEqual" secondItem="iN0-l3-epB" secondAttribute="leading" constant="20" symbolic="YES" id="3pc-w6-uy1"/>
                <constraint firstItem="PEQ-D9-2Vv" firstAttribute="top" relation="greaterThanOrEqual" secondItem="iNa-bH-h1m" secondAttribute="bottom" id="4S3-p0-z6A"/>
                <constraint firstAttribute="trailing" secondItem="PEQ-D9-2Vv" secondAttribute="trailing" constant="10" id="8U0-Fb-3R7"/>
                <constraint firstItem="iNa-bH-h1m" firstAttribute="leading" secondItem="iN0-l3-epB" secondAttribute="leading" constant="15" id="9WK-zC-xET"/>
                <constraint firstAttribute="trailing" secondItem="beR-eV-DX1" secondAttribute="trailing" constant="15" id="BcE-do-dNl"/>
                <constraint firstItem="lp1-oz-XOs" firstAttribute="left" secondItem="iN0-l3-epB" secondAttribute="left" id="BpX-yC-PZG"/>
                <constraint firstItem="PEQ-D9-2Vv" firstAttribute="top" secondItem="2Of-AP-0h9" secondAttribute="bottom" constant="8" symbolic="YES" id="CCg-xe-cKg"/>
                <constraint firstItem="2Of-AP-0h9" firstAttribute="top" secondItem="beR-eV-DX1" secondAttribute="bottom" constant="8" symbolic="YES" id="ESC-Pe-TXR"/>
                <constraint firstItem="iNa-bH-h1m" firstAttribute="bottom" secondItem="2Of-AP-0h9" secondAttribute="bottom" id="GwM-y0-1du"/>
                <constraint firstItem="beR-eV-DX1" firstAttribute="leading" secondItem="iNa-bH-h1m" secondAttribute="trailing" constant="8" symbolic="YES" id="MRN-dd-Oip"/>
                <constraint firstItem="2Of-AP-0h9" firstAttribute="leading" secondItem="GTT-Yh-eSq" secondAttribute="trailing" id="Med-Nd-wEo"/>
                <constraint firstItem="beR-eV-DX1" firstAttribute="top" secondItem="iN0-l3-epB" secondAttribute="top" constant="10" id="Mvs-eV-Wzb"/>
                <constraint firstItem="Ysb-of-cat" firstAttribute="centerY" secondItem="hwF-UL-Q8H" secondAttribute="centerY" id="Rud-i8-Myz"/>
                <constraint firstItem="fNp-yu-K4i" firstAttribute="centerX" secondItem="iN0-l3-epB" secondAttribute="centerX" id="TYN-lq-3DK"/>
                <constraint firstItem="fNp-yu-K4i" firstAttribute="top" secondItem="PEQ-D9-2Vv" secondAttribute="bottom" constant="5" id="V0m-hf-6NS"/>
                <constraint firstItem="GTT-Yh-eSq" firstAttribute="centerY" secondItem="2Of-AP-0h9" secondAttribute="centerY" id="YgR-kp-age"/>
                <constraint firstItem="hwF-UL-Q8H" firstAttribute="leading" secondItem="Ysb-of-cat" secondAttribute="trailing" constant="10" id="aLb-sm-wAb"/>
                <constraint firstAttribute="right" relation="greaterThanOrEqual" secondItem="lp1-oz-XOs" secondAttribute="right" constant="20" symbolic="YES" id="czi-qD-IaJ"/>
                <constraint firstAttribute="trailing" secondItem="E5w-YA-UY8" secondAttribute="trailing" constant="10" id="eNM-dN-tvx"/>
                <constraint firstItem="E5w-YA-UY8" firstAttribute="leading" secondItem="hwF-UL-Q8H" secondAttribute="trailing" constant="10" id="f39-vH-KWq"/>
                <constraint firstItem="iNa-bH-h1m" firstAttribute="leading" secondItem="PEQ-D9-2Vv" secondAttribute="leading" id="mof-5F-8vM"/>
                <constraint firstItem="E5w-YA-UY8" firstAttribute="centerY" secondItem="hwF-UL-Q8H" secondAttribute="centerY" id="rNj-VY-YrO"/>
                <constraint firstItem="E5w-YA-UY8" firstAttribute="top" secondItem="fNp-yu-K4i" secondAttribute="bottom" constant="7.5" id="rup-e7-1CR"/>
                <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="E5w-YA-UY8" secondAttribute="bottom" constant="20" symbolic="YES" id="uEI-XT-igi"/>
            </constraints>
            <connections>
                <outlet property="advertiserView" destination="GTT-Yh-eSq" id="bY8-5O-6fF"/>
                <outlet property="bodyView" destination="PEQ-D9-2Vv" id="Gpd-Q6-Byv"/>
                <outlet property="callToActionView" destination="E5w-YA-UY8" id="RCf-yK-s1x"/>
                <outlet property="headlineView" destination="beR-eV-DX1" id="d1E-ed-yel"/>
                <outlet property="iconView" destination="iNa-bH-h1m" id="gIe-xy-iwm"/>
                <outlet property="mediaView" destination="fNp-yu-K4i" id="624-ZP-L04"/>
                <outlet property="priceView" destination="Ysb-of-cat" id="L6Q-hd-uaJ"/>
                <outlet property="starRatingView" destination="2Of-AP-0h9" id="zCO-9D-S0V"/>
                <outlet property="storeView" destination="hwF-UL-Q8H" id="hRl-23-ce1"/>
            </connections>
            <point key="canvasLocation" x="13.768115942028986" y="-5.6919642857142856"/>
        </view>
    </objects>
    <resources>
        <systemColor name="darkTextColor">
            <color white="0.0" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
        </systemColor>
        <systemColor name="darkTextColor">
            <color white="0.0" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
        </systemColor>
        <systemColor name="darkTextColor">
            <color white="0.0" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
        </systemColor>
        <systemColor name="darkTextColor">
            <color white="0.0" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
        </systemColor>
        <systemColor name="darkTextColor">
            <color white="0.0" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
        </systemColor>
    </resources>
</document>

All suggestions are welcome.