Remove cudf_io namespace alias (#11827)

Some cuIO tests and benchmarks declare `cudf_io` alias for `cudf::io`. This saves a single letter so it's considered to be of very low utility.

Removing all occurrences of this alias.
Also removed a couple of builder calls where the option was being set to default value.

Authors:
  - Vukasin Milovanovic (https://github.com/vuule)

Approvers:
  - Nghia Truong (https://github.com/ttnghia)
  - Bradley Dice (https://github.com/bdice)
  - Yunsong Wang (https://github.com/PointKernel)

URL: #11827

cpp/benchmarks/io/csv/csv_writer.cpp

@@ -26,8 +26,6 @@
 constexpr size_t data_size         = 256 << 20;
 constexpr cudf::size_type num_cols = 64;
 
-namespace cudf_io = cudf::io;
-
 class CsvWrite : public cudf::benchmark {
 };
 
@@ -44,9 +42,9 @@ void BM_csv_write_varying_inout(benchmark::State& state)
   auto mem_stats_logger = cudf::memory_stats_logger();
   for (auto _ : state) {
     cuda_event_timer raii(state, true);  // flush_l2_cache = true, stream = 0
-    cudf_io::csv_writer_options options =
-      cudf_io::csv_writer_options::builder(source_sink.make_sink_info(), view).include_header(true);
-    cudf_io::write_csv(options);
+    cudf::io::csv_writer_options options =
+      cudf::io::csv_writer_options::builder(source_sink.make_sink_info(), view);
+    cudf::io::write_csv(options);
   }
 
   state.SetBytesProcessed(data_size * state.iterations());
@@ -74,12 +72,11 @@ void BM_csv_write_varying_options(benchmark::State& state)
   auto mem_stats_logger = cudf::memory_stats_logger();
   for (auto _ : state) {
     cuda_event_timer raii(state, true);  // flush_l2_cache = true, stream = 0
-    cudf_io::csv_writer_options options =
-      cudf_io::csv_writer_options::builder(source_sink.make_sink_info(), view)
-        .include_header(true)
+    cudf::io::csv_writer_options options =
+      cudf::io::csv_writer_options::builder(source_sink.make_sink_info(), view)
         .na_rep(na_per)
         .rows_per_chunk(rows_per_chunk);
-    cudf_io::write_csv(options);
+    cudf::io::write_csv(options);
   }
 
   state.SetBytesProcessed(data_size * state.iterations());

cpp/benchmarks/io/cuio_common.cpp

@@ -23,8 +23,6 @@
 
 #include <unistd.h>
 
-namespace cudf_io = cudf::io;
-
 temp_directory const cuio_source_sink_pair::tmpdir{"cudf_gbench"};
 
 std::string random_file_in_dir(std::string const& dir_path)
@@ -43,21 +41,21 @@ cuio_source_sink_pair::cuio_source_sink_pair(io_type type)
 {
 }
 
-cudf_io::source_info cuio_source_sink_pair::make_source_info()
+cudf::io::source_info cuio_source_sink_pair::make_source_info()
 {
   switch (type) {
-    case io_type::FILEPATH: return cudf_io::source_info(file_name);
-    case io_type::HOST_BUFFER: return cudf_io::source_info(buffer.data(), buffer.size());
+    case io_type::FILEPATH: return cudf::io::source_info(file_name);
+    case io_type::HOST_BUFFER: return cudf::io::source_info(buffer.data(), buffer.size());
     default: CUDF_FAIL("invalid input type");
   }
 }
 
-cudf_io::sink_info cuio_source_sink_pair::make_sink_info()
+cudf::io::sink_info cuio_source_sink_pair::make_sink_info()
 {
   switch (type) {
-    case io_type::VOID: return cudf_io::sink_info(&void_sink);
-    case io_type::FILEPATH: return cudf_io::sink_info(file_name);
-    case io_type::HOST_BUFFER: return cudf_io::sink_info(&buffer);
+    case io_type::VOID: return cudf::io::sink_info(&void_sink);
+    case io_type::FILEPATH: return cudf::io::sink_info(file_name);
+    case io_type::HOST_BUFFER: return cudf::io::sink_info(&buffer);
     default: CUDF_FAIL("invalid output type");
   }
 }