when using -pipe to generate an svg, trailing whitespace is interpreted as another diagram

[beatchristen]

Given a puml file with trailing whitespace after @enduml, and using the -pipe to process an SVG file, the first generated diagram is succeeded by an empty svg diagram, which makes the SVG invalid XML:

@startuml
Bob->Alice : hello
@enduml

^ two empty lines after @enduml

/usr/bin/java -jar target/plantuml-1.2020.15-SNAPSHOT.jar -nometadata -tsvg -pipe -pipenostderr < trailing-whitespace.puml | xmllint --format -
Some diagram description contains errors
-:1: parser error : Extra content at the end of the document
ust="spacingAndGlyphs" textLength="31" x="37" y="65.0566">hello</text></g></svg>
                                                                               ^

Expectation whas, that those two empty lines after @enduml would just be ignored.

[beatchristen]

The test file for reference
trailing-whitespace.txt