public void writeWithoutExistingContent() {
            buffer.setLength(0);
            existingProfileProperties.clear();

            // Use empty String as input, since we are bootstrapping a new file.
            run(new Scanner(""));
        }
Append the new profiles to the writer, by reading from empty content.
aws-java-sdk-core/src/main/java/com/amazonaws/auth/profile/ProfilesConfigFileWriter.java