public ANTLRInputStream createCopy() {
			ANTLRInputStream stream = new ANTLRInputStream(this.data, this.n);
			stream.name = this.getSourceName();
			return stream;
		}
This method is separate from {@link #parse1} so the first pass can be distinguished when analyzing
 profiler results.
tool-testsuite/test/org/antlr/v4/test/tool/TestPerformance.java