/// <summary>
/// Read the specified number of characters from the buffer, starting
/// at the specified offset into the buffer and writing to the specified
/// offset in the destination buffer.
/// </summary>
/// <param name="sourceIndex">The offset into the buffer at which
/// to start reading.</param>
/// <param name="buffer">The buffer to write the characters to.</param>
/// <param name="destinationIndex">The index in the destination buffer
/// at which to start writing.</param>
/// <param name="count">The number of characters to read.</param>
/// <exception cref="ArgumentNullException">Thrown when <paramref name="buffer"/>
/// is null.</exception>
/// <exception cref="ArgumentOutOfRangeException">Thrown when indicated
/// range would require reading past the end of the the input buffer or
/// writing past the end of the provided output buffer.</exception>
public void ReadAt(int sourceIndex, char[] buffer, int destinationIndex, int count)
{
if (buffer == null)
{
throw new ArgumentNullException(nameof(buffer));
}
if (sourceIndex + count > _buffer.Length)
{
throw new ArgumentOutOfRangeException(nameof(sourceIndex));
}
if (destinationIndex + count > buffer.Length)
{
throw new ArgumentOutOfRangeException(nameof(buffer));
}
_buffer.CopyTo(sourceIndex, buffer, destinationIndex, count);
}