This metaphor almost certainly refers to the practice of establishing the first conditional check in a `while` loop.  If you don't do this, *the loop won't work.*  It is a well-established pattern, and it hasn't changed since the `while` loop was invented.  The requirement for setting the initial condition in a `while` loop is *not a defect.*


    int i = 0; // prime the pump
	while (i < 10)
	{
	    Console.Write("While statement ");
	    // Write the index to the screen.
	    Console.WriteLine(i);
	    // Increment the variable.
	    i++;
	}

The primer can be a read statement, or whatever properly sets the initial condition.  Setting the initial condition using a read statement is called a "Priming Read."

    string line;
    
    using (StreamReader file = new StreamReader("c:\\test.txt"))
    {
        line = file.ReadLine(); // Priming read.
        while(line != null)
        {
            Console.WriteLine (line);
            line = file.ReadLine(); // Subsequent reads.   
        }
    }

In C#, the two `Readline()` calls can be combined into a single statement within the conditional:

    while ((line = r.ReadLine()) != null)
    {
        Console.WriteLine (line);
    }