private void appendIndent(int indent) throws IOException {
        indent *= 4;
        if (indent > sSpace.length()) {
            indent = sSpace.length();
        }
        append(sSpace, 0, indent);
    }
Allocate a FastXmlSerializer with the given internal output buffer size.  If the
size is zero or negative, then the default buffer size will be used.

@param bufferSize Size in bytes of the in-memory output buffer that the writer will use.
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/util/FastXmlSerializer.java