code: @NotNull
  	public static ByteBuf append(@NotNull ByteBuf to, @NotNull byte[] from, int offset, int length) {
  		assert !to.isRecycled();
  		to = ensureWriteRemaining(to, length);
  		to.put(from, offset, length);
  		return to;
  	}
docs: Appends byte array to ByteBuf. If ByteBuf can't accommodate the
  byte array, a new ByteBuf is created which contains all data from
  the original ByteBuf and has enough capacity to accommodate the
  byte array.
  <p>
  ByteBuf must be not recycled before the operation.
  
  @param to the target ByteBuf to which byte array will be appended
  @param from the source byte array to be appended
  @param offset the value of offset for the byte array
  @param length amount of the bytes to be appended to the ByteBuf
  The sum of the length and offset parameters can't
  be greater than the whole length of the byte array
  @return ByteBuf which contains the result of the appending