Conjecture that every graph admits an antimagic orientation

Let $G$ be a finite simple graph. An antimagic orientation of $G$ is an orientation $D$ whose arcs have a bijective labeling by $\{1,\ldots,|A(D)|\}$ with pairwise distinct vertex-sums, where a vertex-sum is the sum of labels on entering arcs minus the sum of labels on leaving arcs. Antimagic-orientation conjecture. Every graph admits an antimagic orientation. The conjecture is motivated by the difficulty of combining antimagic orientations of separate components: although the source knows no counterexamples, it does not give a proof or resolution.