Bidirectional Arrows
Arrows in both directions: `<-->`, `<-.->`, `<==>`.
bidirectional-arrows.mmd
graph LR
A[Client] <-->|sync| B[Server]
B <-.->|heartbeat| C[Monitor]
C <==>|data| D[Storage]Arrows in both directions: `<-->`, `<-.->`, `<==>`.
graph LR
A[Client] <-->|sync| B[Server]
B <-.->|heartbeat| C[Monitor]
C <==>|data| D[Storage]