public void writeInt32NoTag(final int value) throws IOException
    {
        if (value >= 0)
        {
            writeRawVarint32(value);
        }
        else
        {
            // Must sign-extend.
            writeRawVarint64(value);
        }
    }
Write an {@code int32} field to the stream.
protostuff-core/src/test/java/io/protostuff/CodedOutput.java