Proper process for sending Swift events to Javascript in React Native

Question

I've been attempting to build comprehensive Bluetooth functionality, using Swift. I'm currently stuck on how to send events back to React Native from Swift. I attempted this option, but self.bridge is always nil. I'm hoping to build an interface file that will contain everything needed to bridge the functionality I need into Obj-C, and then JS (since I can't make the functions in the Bridge module listeners to NSNotification events or otherwise call them directly in Swift (I think).

BTInterface.swift

@objc(BTInterface)
class BTInterface: NSObject {
    var bridge: RCTBridge!

    @objc func shouldScanForPeripheral(shouldScan: Bool) {
        log.debug("Should scan: \(shouldScan)")
    }

    @objc func testEvent(eventName: String) {
        // self.bridge is always nil and crashes
        self.bridge.eventDispatcher.sendAppEventWithName( eventName, body: "Hello" )
    }
}

BluetoothBridge.m

#import "RCTBridgeModule.h"
#import "RCTEventDispatcher.h"

@interface RCT_EXTERN_MODULE(BTInterface, NSObject)

RCT_EXTERN_METHOD(shouldScanForPeripheral:(BOOL *)shouldScan);
RCT_EXTERN_METHOD(testEvent:(NSString *)eventName)

@end

then I would like to call this from my Bluetooth logic like so:

BTInterface().testEvent("TestEvent")

Exploring some other modules that do similar things, I tried adding the following, to no avail:

added to BTInterface.swift

@objc func initWithBridge(_bridge: RCTBridge) {
    self.bridge = _bridge
}