It looks like memory leak in Utf16ValueStringBuilder.Insert

[martynovs]

Original buffer is not released before assigning new buffer

ZString/src/ZString/Utf16ValueStringBuilder.cs

Lines 309 to 314 in 9837975

	int remainLnegth = this.index - index;
	buffer.AsSpan(index, remainLnegth).CopyTo(newBuffer.AsSpan(newBufferIndex));
	buffer = newBuffer;
	this.index = newBufferIndex + remainLnegth;
	}

For example Grow releases buffer before assigning new one

ZString/src/ZString/Utf16ValueStringBuilder.cs

Lines 139 to 146 in 9837975

	buffer.CopyTo(newBuffer, 0);
	if (buffer.Length != ThreadStaticBufferSize)
	{
	ArrayPool<char>.Shared.Return(buffer);
	}
	buffer = newBuffer;
	}

[neuecc]

thanks, fixed at 2.3.0.