Dependency MQTTnet out of date and has breaking changes.

[Clockwork-Muse]

The dependency for MQTTnet is now at version 4.3.1.873, which includes some breaking changes (or at least some binary incompatibilities).

Attempting a project like so:

<Project Sdk="Microsoft.NET.Sdk.BlazorWebAssembly">

  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="CloudNative.CloudEvents" Version="2.7.1" />
    <PackageReference Include="CloudNative.CloudEvents.Mqtt" Version="2.7.1" />
    <PackageReference Include="CloudNative.CloudEvents.SystemTextJson" Version="2.7.1" />
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly" Version="6.0.18" />
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="6.0.18" PrivateAssets="all" />
    <PackageReference Include="MQTTnet" Version="3.1.2" />
  </ItemGroup>

</Project>

... ends up yielding

dotnet build
MSBuild version 17.3.2+561848881 for .NET
  Determining projects to restore...
  All projects are up-to-date for restore.
/workspaces/event-client/Pages/FetchData.razor(64,30): error CS0012: The type 'MqttApplicationMessage' is defined in an assembly that is not referenced. You must add a reference to assembly 'MQTTnet, Version=3.0.15.0, Culture=neutral, PublicKeyToken=b69712f52770c0a7'. [/workspaces/event-client/event-client.csproj]
/workspaces/event-client/Pages/FetchData.razor(65,37): warning CS8602: Dereference of a possibly null reference. [/workspaces/event-client/event-client.csproj]
/workspaces/event-client/Pages/FetchData.razor(65,26): warning CS8604: Possible null reference argument for parameter 'item' in 'void List<string>.Add(string item)'. [/workspaces/event-client/event-client.csproj]

Build FAILED.

/workspaces/event-client/Pages/FetchData.razor(65,37): warning CS8602: Dereference of a possibly null reference. [/workspaces/event-client/event-client.csproj]
/workspaces/event-client/Pages/FetchData.razor(65,26): warning CS8604: Possible null reference argument for parameter 'item' in 'void List<string>.Add(string item)'. [/workspaces/event-client/event-client.csproj]
/workspaces/event-client/Pages/FetchData.razor(64,30): error CS0012: The type 'MqttApplicationMessage' is defined in an assembly that is not referenced. You must add a reference to assembly 'MQTTnet, Version=3.0.15.0, Culture=neutral, PublicKeyToken=b69712f52770c0a7'. [/workspaces/event-client/event-client.csproj]
    2 Warning(s)
    1 Error(s)

Time Elapsed 00:00:00.73