Fix/stream tracing

[cyve]

Currently in TracedResponse:: toStream(), we end the tracing just after the creation of the stream. But when the server do HTTP streaming, the stream is empty at the beginning, and will be filled progressively. Later in the endTracing() method, we use stream_get_content() to add the response body to the trace attribute, which means PHP waits for the full body to be downloaded before continue to execute some code.

In this PR, we end the tracing when we receive the last chunk of the HTTP response. This allows PHP to continue to execute code asynchronously after the call to toStream(), while the response body is downloaded.