Error: The method 'objectRuntimeType' isn't defined for the class 'BlurHashImage'

[rydein]

Hi, I'm getting this exception while building an app.

Error output from Xcode build:
↳
    ** BUILD FAILED **
Xcode's output:
↳
    Compiler message:
    ../../.pub-cache/hosted/pub.dartlang.org/flutter_blurhash-0.4.0/lib/src/blurhash_image.dart:76:10: Error: The method 'objectRuntimeType' isn't defined for the class 'BlurHashImage'.
     - 'BlurHashImage' is from 'package:flutter_blurhash/src/blurhash_image.dart' ('../../.pub-cache/hosted/pub.dartlang.org/flutter_blurhash-0.4.0/lib/src/blurhash_image.dart').
    Try correcting the name to the name of an existing method, or defining a method named 'objectRuntimeType'.
          '${objectRuntimeType(this, 'BlurHashImage')}(${describeIdentity(blurHash)}, scale: $scale)';
             ^^^^^^^^^^^^^^^^^
    Target kernel_snapshot failed: Exception: Errors during snapshot creation: null
    Failed to build bundle.
    Command PhaseScriptExecution failed with a nonzero exit code
    note: Using new build system
    note: Planning build
    note: Constructing build description
Could not build the precompiled application for the device.

[rydein]

flutter doctor -v
[✓] Flutter (Channel stable, v1.12.13+hotfix.9, on Mac OS X 10.15 19A582a, locale en-JP)
    • Flutter version 1.12.13+hotfix.9 at /Users/rydein/develop/lib/flutter
    • Framework revision f139b11009 (4 weeks ago), 2020-03-30 13:57:30 -0700
    • Engine revision af51afceb8
    • Dart version 2.7.2

[!] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
    • Android SDK at /Users/rydein/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-28, build-tools 28.0.3
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)
    ! Some Android licenses not accepted.  To resolve this, run: flutter doctor --android-licenses

[✓] Xcode - develop for iOS and macOS (Xcode 11.3)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 11.3, Build version 11C29
    • CocoaPods version 1.7.4

[✓] Android Studio (version 3.4)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 37.0.1
    • Dart plugin version 183.6270
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)

[✓] VS Code (version 1.44.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.9.1