Use efficient operations when copying bytes between Dart and Java

[brianquinlan]

• Use the efficiency methods introduced in package:jni 0.7.0 to copy bytes between Dart and Java.
• Reduces the time to copy a 1MB buffer from 400ms to 400µs on Dart 3.1.0

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[HosseinYousefi]

Not directly related to this PR:

1. If you add implementation "com.google.android.gms:play-services-cronet:18.0.1" to the example's app/build.gradle as well (even though it's not necessary – as the plugin has it), jnigen can correctly generate the bindings after running flutter build apk in example/.

2. Consider adding a consumer-rules.pro to cronet and configure it in build.gradle. This will you can keep the cronet classes after tree shaking (in release mode). This way, users don't have to manually add a proguard-rules.pro.

[brianquinlan]

Not directly related to this PR:

1. If you add implementation "com.google.android.gms:play-services-cronet:18.0.1" to the example's app/build.gradle as well (even though it's not necessary – as the plugin has it), jnigen can correctly generate the bindings after running flutter build apk in example/.

Done.

2. Consider adding a consumer-rules.pro to cronet and configure it in build.gradle. This will you can keep the cronet classes after tree shaking (in release mode). This way, users don't have to manually add a proguard-rules.pro.

Done.

[dcharkes]

DBC: Could you post some ball-park perf improvements here?

[HosseinYousefi]

LGTM! Thanks @brianquinlan!

[brianquinlan]

DBC: Could you post some ball-park perf improvements here?

Done in the commit message.

[dcharkes]

• Reduces the time to copy a 1MB buffer from 400ms to 400µs

Sweet!

[dcharkes]

@brianquinlan what Dart/Flutter version was this?

cc @sstrickl our downstream users benefitting from your recent stack of improvements to setRange! 🚀

[brianquinlan]

3.1.0 - I updated the commit message