How to get and print one row from Kafka with pyspark? Queries with streaming sources must be executed with writeStream.start()

I am trying to read some data from Kafka to see what is there.

I wrote

builder = SparkSession.builder\
   .appName("PythonTest01")

spark = builder.getOrCreate()

# Subscribe to 1 topic
df = spark \
  .readStream \
  .format("kafka") \
  .option("kafka.bootstrap.servers", config["kafka"]["bootstrap.servers"]) \
  .option("subscribe", dataFlowTopic) \
  .load()

# df.selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)")

df.printSchema()

df = df.first()

query = df \
    .writeStream \
    .outputMode('complete') \
    .format('console') \
    .start()

query.awaitTermination()

Unfortunately, it swears

pyspark.sql.utils.AnalysisException: Queries with streaming sources must be executed with writeStream.start();

what it wants and how to satisfy it?

If I remove first() it swears

Complete output mode not supported when there are no streaming aggregations on streaming DataFrames/Datasets;

I was to write

#df = df.first()

query = df \
    .writeStream \
    .outputMode('append') \
    .format('console') \
    .start()

query.awaitTermination()

which is printing not first, but last row and not terminates.