code: public final void copyFromUnsafe(int offset, Object source, int sourcePointer, int numBytes) {
  		final long thisPointer = this.address + offset;
  		if (thisPointer + numBytes > addressLimit) {
  			throw new IndexOutOfBoundsException(
  					String.format("offset=%d, numBytes=%d, address=%d",
  							offset, numBytes, this.address));
  		}
  		UNSAFE.copyMemory(source, sourcePointer, this.heapMemory, thisPointer, numBytes);
  	}
docs: Bulk copy method. Copies {@code numBytes} bytes from source unsafe object and pointer.
  NOTE: This is a unsafe method, no check here, please be carefully.
  
  @param offset The position where the bytes are started to be write in this memory segment.
  @param source The unsafe memory to copy the bytes from.
  @param sourcePointer The position in the source unsafe memory to copy the chunk from.
  @param numBytes The number of bytes to copy.
  
  @throws IndexOutOfBoundsException If this segment can not contain the given number
  of bytes (starting from offset).