$ udevadm monitor --env
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[1773.241604] change   /devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sdb/sdb2 (block)
ACTION=change
DEVNAME=/dev/sdb2
DEVPATH=/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sdb/sdb2
DEVTYPE=partition
MAJOR=8
MINOR=18
SEQNUM=2338
SUBSYSTEM=block

KERNEL[1773.244141] remove   /devices/virtual/bdi/8:18-fuseblk (bdi)
ACTION=remove
DEVPATH=/devices/virtual/bdi/8:18-fuseblk
SEQNUM=2339
SUBSYSTEM=bdi

UDEV  [1773.246042] remove   /devices/virtual/bdi/8:18-fuseblk (bdi)
ACTION=remove
DEVPATH=/devices/virtual/bdi/8:18-fuseblk
SEQNUM=2339
SUBSYSTEM=bdi
USEC_INITIALIZED=73244230

KERNEL[1773.745335] add      /devices/virtual/bdi/8:18-fuseblk (bdi)
ACTION=add
DEVPATH=/devices/virtual/bdi/8:18-fuseblk
SEQNUM=2340
SUBSYSTEM=bdi

UDEV  [1773.745822] add      /devices/virtual/bdi/8:18-fuseblk (bdi)
ACTION=add
DEVPATH=/devices/virtual/bdi/8:18-fuseblk
SEQNUM=2340
SUBSYSTEM=bdi
USEC_INITIALIZED=745346

UDEV  [1773.748500] change   /devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sdb/sdb2 (block)
ACTION=change
DEVLINKS=/dev/disk/by-id/ata-ST500LM012_HN-M500MBB_S2U3J9BC447766-part2 /dev/disk/by-id/wwn-0x50004cf207611605-part2 /dev/disk/by-label/System /dev/disk/by-uuid/CCBCC71CBCC70046
DEVNAME=/dev/sdb2
DEVPATH=/devices/pci0000:00/0000:00:1f.2/ata2/host1/target1:0:0/1:0:0:0/block/sdb/sdb2
DEVTYPE=partition
ID_ATA=1
ID_ATA_DOWNLOAD_MICROCODE=1
ID_ATA_FEATURE_SET_APM=1
ID_ATA_FEATURE_SET_APM_CURRENT_VALUE=128
ID_ATA_FEATURE_SET_APM_ENABLED=1
ID_ATA_FEATURE_SET_HPA=1
ID_ATA_FEATURE_SET_HPA_ENABLED=1
ID_ATA_FEATURE_SET_PM=1
ID_ATA_FEATURE_SET_PM_ENABLED=1
ID_ATA_FEATURE_SET_SECURITY=1
ID_ATA_FEATURE_SET_SECURITY_ENABLED=0
ID_ATA_FEATURE_SET_SECURITY_ENHANCED_ERASE_UNIT_MIN=100
ID_ATA_FEATURE_SET_SECURITY_ERASE_UNIT_MIN=100
ID_ATA_FEATURE_SET_SECURITY_FROZEN=1
ID_ATA_FEATURE_SET_SMART=1
ID_ATA_FEATURE_SET_SMART_ENABLED=1
ID_ATA_ROTATION_RATE_RPM=5400
ID_ATA_SATA=1
ID_ATA_SATA_SIGNAL_RATE_GEN1=1
ID_ATA_SATA_SIGNAL_RATE_GEN2=1
ID_ATA_WRITE_CACHE=1
ID_ATA_WRITE_CACHE_ENABLED=1
ID_BUS=ata
ID_FS_LABEL=System
ID_FS_LABEL_ENC=System
ID_FS_TYPE=ntfs
ID_FS_USAGE=filesystem
ID_FS_UUID=CCBCC71CBCC70046
ID_FS_UUID_ENC=CCBCC71CBCC70046
ID_MODEL=ST500LM012_HN-M500MBB
ID_MODEL_ENC=ST500LM012\x20HN-M500MBB\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20
ID_PART_ENTRY_DISK=8:16
ID_PART_ENTRY_NUMBER=2
ID_PART_ENTRY_OFFSET=411648
ID_PART_ENTRY_SCHEME=dos
ID_PART_ENTRY_SIZE=311412729
ID_PART_ENTRY_TYPE=0x7
ID_PART_TABLE_TYPE=dos
ID_REVISION=2AR10001
ID_SERIAL=ST500LM012_HN-M500MBB_S2U3J9BC447766
ID_SERIAL_SHORT=S2U3J9BC447766
ID_TYPE=disk
ID_WWN=0x50004cf207611605
ID_WWN_WITH_EXTENSION=0x50004cf207611605
MAJOR=8
MINOR=18
REMOVE_CMD=/lib/udev/storage-autounmount.sh
SEQNUM=2338
SUBSYSTEM=block
USEC_INITIALIZED=23