public unsafe void Length_Growing_SetsNulls()
        {
            const string Text1 = "foobar";
            var          vsb   = new ValueStringBuilder();

            // Shrink then grow within capacity
            vsb.Append(Text1);
            Assert.Equal(Text1.Length, vsb.Length);
            vsb.Length = 3;
            Assert.Equal(3, vsb.Length);
            vsb.Length = 6;
            Assert.Equal(6, vsb.Length);
            Assert.Equal("foo\0\0\0", vsb.ToString());

            // Grow over capacity
            const string Text2      = "bar";
            Span <char>  stackSpace = stackalloc char[Text2.Length];
            var          vsb2       = new ValueStringBuilder(stackSpace);

            Assert.Equal(0, vsb2.Length);
            vsb2.Append(Text2);
            Assert.True(Text2.AsReadOnlySpan().SequenceEqual(stackSpace), "existing stack buffer should have been used");
            Assert.Equal(Text2.Length, vsb2.Length);
            vsb2.Length = 6;
            Assert.Equal(6, vsb2.Length);
            Assert.Equal("bar\0\0\0", vsb2.ToString());
        }