Project to learn FSM Go implementation, from:

• Finite State Machines in Go
• GFSM - A Simple and Fast FSM for Go

This project also explores:

• One way to handle error (Errors are values, Golang Error Handling lesson by Rob Pike).
• Builder pattern for FSM construction.
• Support states, transition rules, and callback functions.
• Two way to construct fsm using declarative struct based and builder pattern.
• Visualize in Mermaid