ByteData.view(ByteBuffer buffer, [ int offsetInBytes = 0, int length ])

Creates an ByteData view of the specified region in buffer.

Changes in the ByteData will be visible in the byte buffer and vice versa. If the offsetInBytes index of the region is not specified, it defaults to zero (the first byte in the byte buffer). If the length is not specified, it defaults to null, which indicates that the view extends to the end of the byte buffer.

Throws RangeError if offsetInBytes or length are negative, or if offsetInBytes + (length * elementSizeInBytes) is greater than the length of buffer.

Source 

factory ByteData.view(ByteBuffer buffer,
    [int offsetInBytes = 0, int length]) {
  return buffer.asByteData(offsetInBytes, length);
}