Add support to start and end IOTracing through DB APIs (#7203)
Summary:
1. Add support to start io tracing through DB::StartIOTrace(Env*, const TraceOptions&, std::unique_ptr<TraceWriter>&&) and end tracing through DB::EndIOTrace(). This doesn't trace DB::Open.
User side code:
//Open DB
DB::Open(options, dbname, &db);
/* Start tracing */
db->StartIOTrace(env, trace_opt, std::move(trace_writer));
/* Perform Operations */
/*End tracing*/
db->EndIOTrace();
2. Fix the build errors for Windows.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7203
Test Plan: make check -j64
Reviewed By: anand1976
Differential Revision: D22901947
Pulled By: akankshamahajan15
fbshipit-source-id: e59c0b785a802168e6f1aa028d99c224a35cb30c
493f425e77