[SecuritySafeCritical]
    [__DynamicallyInvokable]
    public unsafe StringBuilder Append(string value)
    {
      if (value != null)
      {
        char[] chunkChars = this.m_ChunkChars;
        int chunkLength = this.m_ChunkLength;
        int length = value.Length;
        int num = chunkLength + length;
        if (num < chunkChars.Length)
        {
          if (length <= 2)
          {
            if (length > 0)
              chunkChars[chunkLength] = value[0];
            if (length > 1)
              chunkChars[chunkLength + 1] = value[1];
          }
          else
          {
            fixed (char* smem = value)
              fixed (char* dmem = &chunkChars[chunkLength])
                string.wstrcpy(dmem, smem, length);
          }
          this.m_ChunkLength = num;
        }
        else
          this.AppendHelper(value);
      }
      return this;
    }

    [__DynamicallyInvokable]
    public StringBuilder Append(char value, int repeatCount)
    {
      if (repeatCount < 0)
        throw new ArgumentOutOfRangeException(nameof (repeatCount), Environment.GetResourceString("ArgumentOutOfRange_NegativeCount"));
      if (repeatCount == 0)
        return this;
      int num = this.m_ChunkLength;
      while (repeatCount > 0)
      {
        if (num < this.m_ChunkChars.Length)
        {
          this.m_ChunkChars[num++] = value;
          --repeatCount;
        }
        else
        {
          this.m_ChunkLength = num;
          this.ExpandByABlock(repeatCount);
          num = 0;
        }
      }
      this.m_ChunkLength = num;
      return this;
    }

    private void ExpandByABlock(int minBlockCharCount)
    {
      if (minBlockCharCount + this.Length < minBlockCharCount || minBlockCharCount + this.Length > this.m_MaxCapacity)
        throw new ArgumentOutOfRangeException("requiredLength", Environment.GetResourceString("ArgumentOutOfRange_SmallCapacity"));
      int length = Math.Max(minBlockCharCount, Math.Min(this.Length, 8000));
      this.m_ChunkPrevious = new StringBuilder(this);
      this.m_ChunkOffset += this.m_ChunkLength;
      this.m_ChunkLength = 0;
      if (this.m_ChunkOffset + length < length)
      {
        this.m_ChunkChars = (char[]) null;
        throw new OutOfMemoryException();
      }
      this.m_ChunkChars = new char[length];
    }