code: public int drainTo(@NotNull ByteBuf buf, int length) {
  		assert !buf.isRecycled();
  		assert buf.tail + length <= buf.array.length;
  		drainTo(buf.array, buf.tail, length);
  		buf.tail += length;
  		return length;
  	}
docs: Drains bytes to a given {@code ByteBuf}.
  
  @see #drainTo(byte[], int, int)