TODO: use zaptest.NewLogger(t) instead.

NewT constructs a harness that cleans up after the given test is done.

Buffer is a thread-safe byte buffer.

Harness tracks state for a test, such as temp dirs and IFPS nodes, and cleans them up after the test.

HTTPClient is an HTTP client with some conveniences for testing.

Node is a single Kubo node.

Runner is a process runner which can run subprocesses and aggregate output.

TestLogger is a logger for tests.

Nodes is a collection of Kubo nodes along with operations on groups of nodes.