Convert to streams2 readable streams using through2()

[parshap]

Summary

This patch converts all through streams created using through to be streams2 streams using through2. I ran into an issue where I expected the stream returned by bundle() to buffer data until I read from it (steams2 semantics).

Example

var fs = require("fs");
var browserify = require("browserify");
var output = require("stream-stream")();

output.write(fs.createReadStream("static.js", { encoding: "utf8" });
output.write(browserify("client.js").bundle());
output.end();
output.pipe(fs.createWriteStream("bundle.js"));

The bundle stream emits its data immediately before the stream-stream is ready to read from it. I am interested in hearing if there is a better approach I should be using to concatenate static js to my browserify bundle.

Note: This is broken nondeterministically, only when static.js is sufficiently large.

Details

Tests passed as-is except for test/standalone_events.js. This is because the test is expecting a close event and it seems like streams2 readable streams do not emit one by default nor do they propagate close events from piped streams. I changed this test to note expect a close event.

Many tests use through() and I did not change those - I moved through to devDependencies.

Things to Review

• Usage of objectMode in the right places
• Does anything rely on streams1 semantics (e.g., "auto flowing")? This is kind of an backwards-incompatible API change. I added calls to stream.resume() to automatically start flowing where it made sense (e.g., when there is a callback given).
• Should a close event be emitted?

[ghost]

It might good to bump the major just in case for this one and not worry too much about it.

[ghost]

Merged in 3.37.0. None of the tests broke so I just bumped the minor.