@java.lang.Override
      public final boolean isInitialized() {
        byte isInitialized = memoizedIsInitialized;
        if (isInitialized == 1) return true;
        if (isInitialized == 0) return false;

        memoizedIsInitialized = 1;
        return true;
      }
<pre>
The number of compressed bytes sent or received. If missing, the
compressed size is assumed to be the same size as the uncompressed
size.
</pre>

<code>int64 compressed_size_bytes = 4;</code>

@return The compressedSizeBytes.
java-trace/proto-google-cloud-trace-v2/src/main/java/com/google/devtools/cloudtrace/v2/Span.java