code: void setOffset(long value) {
          if (this.pointer != null && this.offset.get() != this.pointer.getOffset()) {
              // We have already assigned an offset to this.
              throw new IllegalStateException("Cannot assign offset more than once.");
          }
  
          this.offset.set(value);
      }
docs: Updates the offset of the wrapped BTreePage.
  
  @param value The offset to assign.