PySpark RDD <foreach> print does not produce any output

```
import findspark
findspark.init()

import pyspark
sc = pyspark.SparkContext(appName="RDD (no)Print")

sc.textFile("/user/hadoop/input/dummy.txt").foreach(lambda x:print(x))

sc.stop()
```
The above code does not produce any output. The same example works just fine within pyspark console.

The issue provides only a Python reproducer using findspark, pyspark.SparkContext, textFile, and RDD.foreach; no repository file or test is named. First reproduce the difference between a notebook and the pyspark console, then trace how worker output is handled in the notebook environment. Done means the output behavior is explained and a regression test or documented resolution covers the reproducer.

Written by the indexing model from the issue text.