0.0.6

What's changed

• Added opt-in diagnostic tracing for real Spanner/FPM performance investigations.
  • LARAVEL_SPANNER_TRACE=1 records Laravel benchmark app step timings as NDJSON.
  • GRPC_LITE_TRACE_FILE=/path/to/trace.ndjson records php-grpc-lite RPC completion events (rpc.end) with method, status, elapsed time, payload sizes, and connection reuse information.
• Added tools/benchmark/spanner-trace-summary.php to summarize trace files.
• Preserved duplicate request metadata values, including CallCredentials-provided metadata with the same key as existing request metadata.

Notes

• Tracing is disabled by default. When the trace env vars are unset, this release does not perform trace file I/O.
• The trace facility is intended for diagnosing the reported real Spanner/ext-grpc comparison gap. It is not a performance fix claim.