fix(android): the cast relay spools a receiver's lead to disk

Fragments are 5-10 MB at a film's bitrate; dropped past 8 MB in memory, the
TV froze for their length. Each receiver now reads from its own spool file,
deleted with it; nothing is dropped short of a disk bound.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/packages/meshbay-hub/tests/test_android_cast.py b/packages/meshbay-hub/tests/test_android_cast.py
index 0ff383a..a346d15 100644
--- a/packages/meshbay-hub/tests/test_android_cast.py
+++ b/packages/meshbay-hub/tests/test_android_cast.py
@@ -53,7 +53,6 @@ def test_the_relay_keeps_the_desktop_mitigations():
     for name in ("RING_CAP", "PORT_BASE", "PORT_COUNT"):
         js = re.search(rf"const {name} = (\d+);", desktop).group(1)
         assert re.search(rf"const val {name} = {js}\b", relay), name
-    assert "BACKPRESSURE_HIGH = 8L * 1024 * 1024" in relay
     assert "InetSocketAddress(address, PORT_BASE + i)" in relay, "bound to the LAN address"
     # Code, not comments: the comment saying "never 0.0.0.0" is not a bind.
     code = re.sub(r"/\*.*?\*/", "", relay, flags=re.S)
@@ -65,6 +64,21 @@ def test_the_relay_keeps_the_desktop_mitigations():
     assert serve.index('method == "OPTIONS"') < serve.index('query["t"] != token')
 
 
+def test_what_a_receiver_has_not_read_waits_on_disk():
+    """The desktop drops a fragment once 8 MB wait for a receiver; a fragment
+    is 5 to 10 MB at a film's bitrate, so the television froze for its length
+    (measured: three dropped in the first fifteen seconds). Here the lead waits
+    in a spool file per receiver, deleted with it, and is dropped only past a
+    disk bound."""
+    relay = _read(CAST / "CastRelay.kt")
+    assert "BACKPRESSURE_HIGH" not in relay
+    assert "RandomAccessFile(file, \"rw\").channel" in relay
+    assert "c.waiting() > spoolLimit()" in relay
+    assert "SPOOL_MAX_BYTES = 2L * 1024 * 1024 * 1024" in relay
+    assert "file.delete()" in relay
+    assert 'java.io.File(context.cacheDir, "cast-relay")' in _read(CAST / "CastChannels.kt")
+
+
 def test_the_backlog_is_bounded_in_bytes():
     """A fragment is a segment, megabytes at a film's bitrate: 64 of them killed
     the application with an OutOfMemoryError on the emulator."""