How would you describe a long-awaited event that is finally happening?

Describing a long-awaited event that is finally happening aligns perfectly with the term "protracted." This term indicates that a process or situation has taken a considerable amount of time, suggesting anticipation and delay before culmination. When something is described as protracted, it evokes the feeling of a lengthy wait, emphasizing the significance of the event now taking place after much time has passed.

In contrast, terms like "instantaneous," "spontaneous," and "immediate" do not fit the context of a long-awaited event. "Instantaneous" suggests something occurring without any delay, while "spontaneous" refers to something occurring without prior planning or deliberation. "Immediate" implies a sense of urgency or promptness, lacking the connotation of a long period of waiting. Therefore, "protracted" is most appropriate for conveying the essence of a long-anticipated event that is finally unfolding.