public override void Write()

in src/RecyclableMemoryStream.cs [979:1036]
48 lines of code
7 McCabe index (conditional complexity)

        public override void Write(byte[] buffer, int offset, int count)
        {
            this.CheckDisposed();
            if (buffer == null)
            {
                throw new ArgumentNullException(nameof(buffer));
            }

            if (offset < 0)
            {
                throw new ArgumentOutOfRangeException(nameof(offset), offset,
                    $"{nameof(offset)} must be in the range of 0 - {nameof(buffer)}.{nameof(buffer.Length)}-1.");
            }

            if (count < 0)
            {
                throw new ArgumentOutOfRangeException(nameof(count), count, $"{nameof(count)} must be non-negative.");
            }

            if (count + offset > buffer.Length)
            {
                throw new ArgumentException($"{nameof(count)} must be greater than {nameof(buffer)}.{nameof(buffer.Length)} - {nameof(offset)}.");
            }

            int blockSize = this.memoryManager.BlockSize;
            long end = (long)this.position + count;

            this.EnsureCapacity(end);

            if (this.largeBuffer == null)
            {
                int bytesRemaining = count;
                int bytesWritten = 0;
                var blockAndOffset = this.GetBlockAndRelativeOffset(this.position);

                while (bytesRemaining > 0)
                {
                    byte[] currentBlock = this.blocks[blockAndOffset.Block];
                    int remainingInBlock = blockSize - blockAndOffset.Offset;
                    int amountToWriteInBlock = Math.Min(remainingInBlock, bytesRemaining);

                    Buffer.BlockCopy(buffer, offset + bytesWritten, currentBlock, blockAndOffset.Offset,
                                     amountToWriteInBlock);

                    bytesRemaining -= amountToWriteInBlock;
                    bytesWritten += amountToWriteInBlock;

                    ++blockAndOffset.Block;
                    blockAndOffset.Offset = 0;
                }
            }
            else
            {
                Buffer.BlockCopy(buffer, offset, this.largeBuffer, (int)this.position, count);
            }
            this.position = end;
            this.length = Math.Max(this.position, this.length);
        }