public Builder setAttributes(com.google.devtools.cloudtrace.v2.Span.Attributes value) {
        if (attributesBuilder_ == null) {
          if (value == null) {
            throw new NullPointerException();
          }
          attributes_ = value;
        } else {
          attributesBuilder_.setMessage(value);
        }
        bitField0_ |= 0x00000008;
        onChanged();
        return this;
      }
<pre>
A set of attributes on the link. Up to 32 attributes can be
specified per link.
</pre>

<code>.google.devtools.cloudtrace.v2.Span.Attributes attributes = 4;</code>
java-trace/proto-google-cloud-trace-v2/src/main/java/com/google/devtools/cloudtrace/v2/Span.java