private com.google.protobuf.MapField<
            java.lang.String, com.google.devtools.cloudtrace.v2.AttributeValue>
        internalGetAttributeMap() {
      if (attributeMap_ == null) {
        return com.google.protobuf.MapField.emptyMapField(
            AttributeMapDefaultEntryHolder.defaultEntry);
      }
      return attributeMap_;
    }
<pre>
A set of attributes as key-value pairs.
</pre>

Protobuf type {@code google.devtools.cloudtrace.v2.Span.Attributes}
java-trace/proto-google-cloud-trace-v2/src/main/java/com/google/devtools/cloudtrace/v2/Span.java