feat: Add logger for transport usage

Author: HazAT

packages/core/src/basebackend.ts

@@ -94,6 +94,7 @@ export abstract class BaseBackend<O extends Options> implements Backend {
    * @inheritDoc
    */
   public sendEvent(event: Event): void {
+    logger.log(`Sending event with ${this.transport.constructor.name}`);
     this.transport.sendEvent(event).catch(reason => {
       logger.error(`Error while sending event: ${reason}`);
     });

packages/opentracing/src/spancontext.ts

@@ -5,13 +5,13 @@ import { uuid4 } from '@sentry/utils/misc';
 export class SpanContext {
   public constructor(
     public readonly traceId?: string,
-    public readonly spanId: string = uuid4(), // private readonly parentId: string,
+    public readonly spanId: string = uuid4().substring(16), // private readonly parentId: string,
   ) {}
 
   /**
    * Returns debug version of the span.
    */
   public toString(): string {
-    return `TraceId: ${this.traceId} SpanId: ${this.spanId}`;
+    return `${(this.traceId && `trace-id:${this.traceId};`) || ''}span-id:${this.spanId}`;
   }
 }