code: public AutofillSubjectBuilder text(String... firstLinePrefixes) {
  		this.firstLinePrefixes.addAll(Arrays.asList(firstLinePrefixes));
  		return myself;
  	}
docs: Uses first line of text template to define the email subject (only if a
  prefix is defined).
  
  You can specify a direct value. For example:
  
  <pre>
  .text("Subject:");
  </pre>
  
  <p>
  You can also specify one or several property keys. For example:
  
  <pre>
  .text("${custom.property.high-priority}", "${custom.property.low-priority}");
  </pre>
  
  The properties are not immediately evaluated. The evaluation will be done
  when the {@link #build()} method is called.
  
  If you provide several property keys, evaluation will be done on the
  first key and if the property exists (see {@link EnvironmentBuilder}),
  its value is used. If the first property doesn't exist in properties,
  then it tries with the second one and so on.
  
  @param firstLinePrefixes
  one value, or one or serveral property keys
  @return this instance for fluent chaining