Channel Buffering in Visual Basic .NET

Our first example demonstrates channel buffering. By default, channels are unbuffered, meaning that they will only accept sends if there is a corresponding receive ready to receive the sent value. Buffered channels accept a limited number of values without a corresponding receiver for those values.

Imports System

Module ChannelBuffering
    Sub Main()
        ' Here we create a channel of strings buffering up to 2 values.
        Dim messages As New System.Collections.Concurrent.BlockingCollection(Of String)(2)

        ' Because this collection is buffered, we can add these
        ' values without a corresponding concurrent receive.
        messages.Add("buffered")
        messages.Add("channel")

        ' Later we can receive these two values as usual.
        Console.WriteLine(messages.Take())
        Console.WriteLine(messages.Take())
    End Sub
End Module

To run the program, save it as ChannelBuffering.vb and use the Visual Basic compiler:

$ vbc ChannelBuffering.vb
$ ChannelBuffering.exe
buffered
channel

In this Visual Basic .NET example, we use the BlockingCollection(Of T) class from the System.Collections.Concurrent namespace to simulate a buffered channel. This collection allows us to specify a maximum capacity, which acts similar to a buffered channel in other languages.

The Add method is used to send values to the collection, while the Take method is used to receive values. These operations are thread-safe and can be used concurrently.

Note that Visual Basic .NET doesn’t have built-in channel primitives like some other languages, so we use concurrent collections to achieve similar functionality. The BlockingCollection(Of T) provides thread-safe operations for adding and removing items, making it suitable for producer-consumer scenarios.