docs: protected void mergeWith(Entry other) {
          // We should only merge entries in leafs, and leafes should have empty
          // buffers.
          assert (this.child == null);
          assert (other.child == null);
          assert (other.buffer.isEmpty());
  
          this.data.add(other.data);
          if (this.timestamp < other.timestamp) {
              this.timestamp = other.timestamp;
          }
      }