It looks like memory leak in Utf16ValueStringBuilder.Insert

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; 
        
           }

thanks, fixed at 2.3.0.

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

	buffer = newBuffer;
	this.index = newBufferIndex + remainLnegth;
	}

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

	buffer = newBuffer;
	}