public HttpSource postData(String payload) {
		String command = String.format(
				"http post --target http://" + host + ":%d --data \"%s\"",
				port, payload.replace("\"", "\\\""));
		if (contentType != null) {
			command += String.format(" --contentType \"%s\"", contentType);
		}
		CommandResult result = shell.executeCommand(command);
		Assert.isTrue(result.isSuccess(), "http post failed. Command result: " + result.getException());
		return this;
	}
Attempts connections to the source until it is ready to accept data.
spring-xd-shell/src/test/java/org/springframework/xd/shell/command/fixtures/HttpSource.java