document span_data.h

Author: dgoffredo

src/datadog/span_data.h

@@ -1,5 +1,8 @@
 #pragma once
 
+// This component provides a `struct`, `SpanData`, that contains all data fields
+// relevant to `Span`. `SpanData` is what is consumed by `Collector`.
+
 #include <cstddef>
 #include <memory>
 #include <optional>
@@ -33,10 +36,16 @@ struct SpanData {
   std::optional<std::string_view> environment() const;
   std::optional<std::string_view> version() const;
 
+  // Modify the properties of this object to honor the specified `config` and
+  // `defaults`.  The properties of `config`, if set, override the properties of
+  // `defaults`. Use the specified `clock` to provide a start none of none is
+  // specified in `config`.
   void apply_config(const SpanDefaults& defaults, const SpanConfig& config,
                     const Clock& clock);
 };
 
+// Append to the specified `destination` the MessagePack representation of the
+// specified `span`.
 Expected<void> msgpack_encode(std::string& destination, const SpanData& span);
 
 }  // namespace tracing