aws-lambda-rust-runtime: Panic at 'Could not retrieve next event'

I thought maybe it was something in my code but I get the same panic with the example here: https://docs.rs/crate/lambda_runtime/0.2.0

START RequestId: 967aad3f-eaaa-4946-bc51-dc717f81aa71 Version: $LATEST
thread 'main' panicked at 'Could not retrieve next event', /Users/redacted/.cargo/registry/src/github.com-1ecc6299db9ec823/lambda_runtime_core-0.1.0/src/runtime.rs:266:17
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:71
   2: std::panicking::default_hook::{{closure}}
             at src/libstd/sys_common/backtrace.rs:59
             at src/libstd/panicking.rs:211
   3: std::panicking::default_hook
             at src/libstd/panicking.rs:227
   4: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:491
   5: std::panicking::begin_panic
   6: <lambda_runtime_core::runtime::Runtime<Function, EventError>>::get_next_event
   7: <lambda_runtime_core::runtime::Runtime<Function, EventError>>::get_next_event
   8: <lambda_runtime_core::runtime::Runtime<Function, EventError>>::get_next_event
   9: <lambda_runtime_core::runtime::Runtime<Function, EventError>>::get_next_event
  10: <lambda_runtime_core::runtime::Runtime<Function, EventError>>::get_next_event
  11: lambda_runtime_core::runtime::start_with_config
  12: bootstrap::main
  13: std::rt::lang_start::{{closure}}
  14: std::panicking::try::do_call
             at src/libstd/rt.rs:59
             at src/libstd/panicking.rs:310
  15: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:102
  16: std::rt::lang_start_internal
             at src/libstd/panicking.rs:289
             at src/libstd/panic.rs:398
             at src/libstd/rt.rs:58
  17: main
END RequestId: 967aad3f-eaaa-4946-bc51-dc717f81aa71
REPORT RequestId: 967aad3f-eaaa-4946-bc51-dc717f81aa71	Duration: 1050.16 ms	Billed Duration: 1100 ms 	Memory Size: 128 MB	Max Memory Used: 26 MB	
RequestId: 967aad3f-eaaa-4946-bc51-dc717f81aa71 Error: Runtime exited with error: exit status 101
Runtime.ExitError