Add interfaces and tests in DTSpan to finish a span

Signed-off-by: Emelia Lei <[email protected]>

Author: emelialei88

Diff for: src/groups/bmq/bmqimp/bmqimp_brokersession.t.cpp

@@ -2798,6 +2798,12 @@ class DTTestSpan : public bmqpi::DTSpan {
     {
         return d_operation;
     }
+
+    int finish() const BSLS_KEYWORD_OVERRIDE
+    {
+        // NOT IMPLEMENTED
+        return 0;
+    }
 };
 
 class DTTestTracer : public bmqpi::DTTracer {

Diff for: src/groups/bmq/bmqpi/bmqpi_dtspan.h

@@ -56,6 +56,13 @@ class DTSpan {
     /// Returns the name of the operation that this `DTSpan` represents.
     virtual bsl::string_view operation() const = 0;
 
+    /// Mark the end of the `DTSpan`. Only the timing of the first call for a
+    /// given `DTSpan` will be recorded, and implementations are free to ignore
+    /// all further calls.  A finished Span can not be re-started. If finish()
+    /// is not directly called, it will be called from the destructor.
+    /// Return 0 on success, or a non-zero error code on error.
+    virtual int finish() const = 0;
+
     // =============
     // class Baggage
     // =============

Diff for: src/groups/bmq/bmqpi/bmqpi_dtspan.t.cpp

@@ -29,6 +29,7 @@ using namespace BloombergLP;
 /// A test implementation of the `bmqpi::DTSpan` protocol.
 struct DTSpanTestImp : public bsls::ProtocolTestImp<bmqpi::DTSpan> {
     bsl::string_view operation() const BSLS_KEYWORD_OVERRIDE;
+    int              finish() const BSLS_KEYWORD_OVERRIDE;
 };
 
 // Define one of DTSpanTestImp methods out-of-line, to instruct the compiler to
@@ -38,6 +39,11 @@ bsl::string_view DTSpanTestImp::operation() const
     return markDone();
 }
 
+int DTSpanTestImp::finish() const
+{
+    return markDone();
+};
+
 // ============================================================================
 //                                    TESTS
 // ============================================================================