public String getPidFileName() {
    return System.getProperty(PROPERTY_TEST_PREFIX, EMPTY) + fileName
        + '.' + SUFFIX_PID;
  }
Enumeration of GemFire {@link ControllableProcess} types and the file names associated with
controlling its lifecycle.

@since GemFire 8.0
geode-core/src/main/java/org/apache/geode/internal/process/ProcessType.java