Christopher Vourlias When he began working on his latest documentary, “The Last Seagull,” acclaimed Bulgarian filmmaker Tonislav Hristov (“The Good Postman”) set himself a seemingly simple task: to follow the last of the dying breed of male escorts who, since the communist era, have spent their summers seducing foreign women in resort towns along the Black Sea. That plan went astray, however, when real-world events intervened: first the coronavirus pandemic, which grounded flights and shuttered the very resorts where those escorts plied their trade; then the war in Ukraine, which impacted “The Last Seagull” in unexpected ways. “This is what’s nice, but also scary, about documentaries,” Hristov told Variety after the film’s world premiere at the Thessaloniki Intl. Documentary Festival. “You never know what’s going to happen next.”